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The GHS OSHA Chemical Labeling Guide

Introduction

Dr. Reale is a co-author of Material Safety Data Sheets – The Writer’s Desk Reference, authored a chapter in Improving Safety in the Chemical Laboratory, and provided informative responses to questions for Compliance Magazine. He was a long-standing member of the Board of Directors of the Society for Chemical Hazard Communication and a past chairman of its Program and Standards Review Committees. He belongs to the American Chemical Society and the National Fire Protection Association. Dr. Reale earned his doctoral and master’s degrees in organic chemistry from Fordham University, and a B.S. in chemistry from St. Peter’s College.
Dr. Reale
The rules and regulations in the US for communicating hazards of chemicals1 developed in an unsystematic manner as government agencies acted independently in creating systems applicable to their separate mandates. Thus, for example, the Environmental Protection Agency (EPA) is responsible for finished pesticide products. and the Consumer Product Safety Commission (CPSC) oversees various products sold to consumers. The Occupational Safety and Health Administration (OSHA), on the other hand, covers the workplace. In the case of pesticides and consumer products, OSHA regulates the manufacture of these types of products, while the other agencies regulate those products in their final form. When chemical products are shipped, they become subject to the US Department of Transportation (DOT) regulations.
Because there was no coordination between these agencies as they were developing their regulations, a chemical could be hazardous in one system, and not regulated in another. The label that was required for a product could be very different, depending on the market in which it was being sold.
A similar thing happened internationally. Each country or region developed its own hazard communication programs, with its own classification schemes and labeling requirements. Canada’s workplace rules (Controlled Products Regulations) were similar to those of OSHA, but it requires pictograms on labels, which OSHA did not. The European Union had a system in place since 1967 which was very different than that of either the US or Canada.
As a simple example, consider “Sneeze Right,” a hypothetical product containing 1% of a chemical that is a respiratory sensitizer. The following are the workplace labels that would have been required:
US Canada2 Europe3 Transport
Sneeze Right Lung sensitizer. ABC Chemical Co. 384 Industrial Way Bayonne, NJ Sneeze Right Very toxic. Lung sensitizer. Do not breathe vapors or mist. If inhaled, remove patient to fresh air and get medical attention. See Material Safety Data Sheet ABC Chemical Co. Montreal, Canada. Sneeze Right Contains 1,5-naphthylenediisocyanate Harmful May cause sensitization by inhalation. Do not breathe fumes or vapours. This material and its container must be disposed of as hazardous waste. ABC Chemical Co. London, England 011 44 115 9651878 Not classified as hazardous. No label required
Although both Canada and the European Union require pictograms on a label, they are different, and, as you can see from the examples, neither is intuitive. In the case of Canada, the symbols required for pesticides and for consumer products are different from one another and from the workplace.
Interestingly, if the chemical that causes respiratory sensitization were present at 0.9%, it would only be regulated by Canada.

Genesis of the Globally Harmonized System

The example discussed above is from the workplace sector4, but similar disparities could be presented for consumer chemicals or pesticides. That is to say, the classification criteria are different, and the labeling elements are region specific. It is difficult to rationalize how a product could be “dangerous” in one country, but "safe" in another.
For many years the transport sector had a uniform system for the classification and labeling of products through the efforts of the United Nations Committee of Experts on the Transportation of Dangerous Goods (UNCETDG), but its work was restricted to physical hazards and acute toxicity. Further, the scope of the recommendations dealt with the products during transportation – not use. For this reason, long term health effects were not addressed.
Although the need for a consistent system of classification and hazard communication for all aspects of a chemical product’s life cycle was recognized for a long time by regulators and the regulated community alike, the real impetus for creating such a system occurred at the 1992 United Nations Conference on Environment and Development held in 1992 in Brazil. Agenda 21, paragraph 19.27 stated:
A globally harmonized hazard classification and compatible labelling system, including material safety data sheets and easily understandable symbols, should be available, if feasible, by the year 2000.
The work in developing the system was assigned to three groups: UNCETDG, which was responsible for physical hazards; Organization for Economic Cooperation and Development (OECD), which was responsible for health and environmental hazards; and International Labour Organization (ILO), which was responsible for labels and safety data sheets. These three organizations based their work on: the existing systems of Canada and the US for the workplace, consumer products and pesticides; the European directives on dangerous substances and preparations; and, the UN Orange Book5. The key guiding principles that the group agreed to follow were:
  • Protection will not be reduced
  • The system will be based on intrinsic properties (hazards) of chemicals
  • All types of chemicals will be covered
  • All systems will have to be changed
  • Involvement of all stakeholders should be ensured
  • Comprehensibility must be addressed
Their work was completed in 2001, and the resulting system was transferred to the newly created United Nations Subcommittee of Experts on the Globally Harmonized System of Classification and Labelling of Chemicals (UNSCEGHS). This body is responsible for maintaining the system and for promoting its implementation. The UNSCEGHS published the first version of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) in 2003, which has become known as the UN Purple Book. The subcommittee works on a biennial basis, and has since revised the Purple Book four times; Revision 4 was published in 2011 and is available from the United Nations bookstore6.

GHS Implementation

Shortly after the first Purple Book was published, the World Summit on Sustainable Development met in Johannesburg and issued a Plan of Implementation for GHS that encouraged countries to implement the GHS by 2008. Although several smaller countries did indeed develop GHS based programs and many have work underway7, the first major region to do so was the European Union which issued its CLP Regulation8 on December 16, 2008. The CLP regulation established a phase-in period during which both the current legislation and the new Regulation will be in place. It became effective for substance on December 1, 2010, and will be for mixtures on June 1, 2015.
In the US, OSHA issued a final rule on March 26, 2012 adapting its workplace regulations to conform to the GHS. As the EU did, the OSHA rule provides for several transition periods:
December 1, 2013 Train employees in label elements and SDS.
June 1, 2015 Comply with all requirements of final rule.
December 1, 2015 Distributers must assure that labels on shipped containers contain new label elements.
June 1, 2016
  • Employers must:
  • Update workplace labeling
  • Update hazard communication program
  • Train employee about new health and physical hazards.
OSHA set its date for compliance to coincide with that of the EU. Note that OSHA permits voluntary compliance before the dates in the above table.
The pesticides and consumer product sectors in the US are still in the early stages of aligning their regulations with the GHS. (See Footnote7 for details.)
Progress on GHS implementation is slow in Canada. The following tentative dates have been established by Health Canada for updating its Workplace Hazardous Materials Information System to conform to the GHS9 :
  • Proposed regulations released March 2013
  • Final regulations released Jan 2014
  • Implementation start date July 2015
As in the US, changes in the Canadian pesticide and consumer products regulations are in the early stages of development. (See Footnote7 for details.)
The transport sector is in compliance with the GHS because all countries use the United Nations Recommendations on the Transport of Dangerous Goods (the Orange Book) as the basis for their transportation regulations10.

Overview of GHS

The GHS covers all hazardous chemicals and may be adopted to cover chemicals in the workplace and in transport, consumer products, pesticides and pharmaceuticals. The target audiences for the GHS include workers, transport workers, emergency responders and consumers. The GHS system was not written as a model standard or a regulation that a country could "cut and paste" in creating its own law or regulation. The GHS standardizes and harmonizes the classification of, and hazard communication for, chemicals. It is a logical and comprehensive approach that:
  • Defines criteria for health, physical and environmental hazards of chemicals
  • Communicates hazard and precautionary information through labels and Safety Data Sheets (SDS).
  • Provides explanatory information on how to apply the system
It utilizes a so-called "building block" approach, whereby each country could select those elements appropriate to its different sectors (workplace, transportation, consumers, and pesticides) in creating its own regulations. As pointed out above, the GHS classification system covers three hazard groups:
  • Physical hazards
  • Health hazards
  • Environmental hazards
Within each of these there are "classes" and "categories". Each of these parts is called a "building block". Each country can determine which building blocks of the GHS system it will use. However, once building blocks are chosen, the corresponding GHS rules for classification and hazard communication must be used. This building block approach provides flexibility, yet maintains uniformity, thereby achieving the overarching goal of harmonization across countries and within sectors.
The GHS also allows countries to keep national requirements that it does not cover11 and to adopt the system taking into account the various target audiences in different legal areas.
A critically important aspect of the GHS is that the hazard communication requirements, particularly label elements, are specified for each hazard class and category. This avoids the confusion apparent in Figure 1, wherein text and symbols are different or non-existent. Therefore, each of the three chapters of the Purple Book covering physical, health and environmental hazards contains a section on hazard communication that lists the symbol, signal word and hazard statements. We will learn later that precautionary measures are also provided in an Annex.

GHS Physical Hazards

Before one can classify a substance or a mixture as to its hazards, the physical state must be ascertained. The GHS provides the following definitions:
  • a gas is a substance or mixture which at 50° C has a vapor pressure greater than 300 kPa; or is completely gaseous at 20° C and a standard pressure of 101.3 kPa.
  • a liquid is a substance or mixture that is not a gas and which has a melting point or initial melting point of 20° C or less at standard pressure of 101.3 kPa.
  • a solid is a substance or mixture that does not meet the definitions of a liquid or a gas.
Substances and mixtures are generally classified on the basis of test data which are specified in Part 2 of the GHS. The GHS provides guidance with practical information to assist in applying the criteria. Note: for some physical hazard classes, the chapters contain methods for classifying mixtures based upon component information.
The following are the physical hazards that have been described by the GHS:
  • Explosives12. This class includes the following, either as is or as an article13:
    • An explosive substance (or mixture) is a solid or liquid which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings. Pyrotechnic substances are included even when they do not evolve gases.
    • A pyrotechnic substance (or mixture) is designed to produce an effect by heat, light, sound, gas or smoke or a combination of these as the result of non-detonative, self-sustaining, exothermic chemical reactions.
    There a six divisions within the Explosives Class.
  • Flammable Gases14. Flammable gas means a gas having a flammable range in air at 20° C and a standard pressure of 101.3 kPa. Substances and mixtures of this hazard class are assigned to one of two hazard categories.
  • Flammable Aerosols15. Aerosols, this means aerosol dispensers, are any non-refillable container made of metal, glass or plastics and containing any gas compressed, liquefied or dissolved under pressure with or without a liquid, paste or powder, and fitted with a release device allowing the contents to be ejected as solid or liquid particles in suspension in a gas, as a foam, paste or powder or in a liquid or gaseous state.
    Flammable aerosols are assigned to one of two categories on the basis of:
    • Its components
    • Its chemical heat of combustion, and if applicable
    • Results from the foam test for foam aerosols
    • Ignition distance test and enclosed space test for spray aerosols
  • Oxidizing Gases16. An oxidizing gas is any gas which may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does. Substances and mixtures of this hazard class are assigned to a single hazard category.
  • Gases under Pressure17. An oxidizing gas is any gas which may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does. Substances and mixtures of this hazard class are assigned to a single hazard category.
  • Flammable Liquids18. Flammable liquid means a liquid having a flash point of not more than 93° C. Substances and mixtures of this hazard class are assigned to one of four hazard categories on the basis of the flash point and boiling point. This class does not include aerosols, which should be classified as discussed above.
  • Flammable Solids19. This class includes:
    • A flammable solid that is a solid that is readily combustible, or may cause or contribute to fire through friction.
    • Readily combustible solids that are powdered, granular, or pasty substances which are dangerous if they can be easily ignited by brief contact with an ignition source, such as a burning match, and if the flame spreads rapidly.
    Substances and mixtures of this hazard class are assigned to one of two hazard categories on the basis of test data20. The tests include burning time, burning rate and behavior of fire in a wetted zone of the test sample.
  • Self-reactive Substances and Mixturess21. Self-reactive substances are thermally unstable liquid or solid substances or mixtures liable to undergo a strongly exothermic thermal decomposition even without participation of oxygen (air). This definition excludes materials classified under the GHS as explosive, organic peroxides or as oxidizing. The following substances and mixtures are also excluded from this class:
    • Those whose heat of decomposition is less than 300 J/g; or,
    • Those whose self-accelerating decomposition temperature (SADT) is greater than 75° C for a 50 kg package.
    Substances and mixtures of this hazard class are assigned to one of seven “types, A to G” on the basis of the outcome of specific tests22 .
  • Pyrophoric Liquids23. A pyrophoric liquid is a liquid which, even in small quantities, is liable to ignite within five minutes after coming into contact with air. Substances and mixtures of this hazard class are assigned to a single hazard category on the basis of test data24.
  • Pyrophoric Solids25. A pyrophoric solid is a solid which, even in small quantities, is liable to ignite within five minutes after coming into contact with air. Substances and mixtures of this hazard class are assigned to a single hazard category on the basis of test data 26.
  • Self-heating Substances and Mixtures27. A self-heating substance is a solid or liquid, other than a pyrophoric substance, which, by reaction with air and without energy supply, is liable to self-heat. This endpoint differs from a pyrophoric substance in that it will ignite only when in large amounts (kilograms) and after long periods of time hours or days). Substances and mixtures of this hazard class are assigned to one of two hazard categories on the basis of test data28.
  • Substances which on Contact with Water Emit Flammable Gases29. Substances or mixtures which, in contact with water, emit flammable gases are solids or liquids which, by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities. Substances and mixtures of this hazard class are assigned to one of three hazard categories on the basis of test results which measure the rate of flammable gas evolution30.
  • Oxidizing Liquids31. An oxidizing liquid is a liquid which, while in itself not necessarily combustible, may, generally by yielding oxygen, cause or contribute to the combustion of other material. Substances and mixtures of this hazard class are assigned to one of three hazard categories on the basis of test results which measure ignition or pressure rise time compared to defined mixtures32.
  • Oxidizing Solids33. An oxidizing solid is a solid which, while in itself not necessarily combustible, may, generally by yielding oxygen, cause or contribute to the combustion of other material. Substances and mixtures of this hazard class are assigned to one of three hazard categories on the basis of test results which measure mean burning time compared to specified control mixture34.
  • Organic Peroxides35.An organic peroxide is an organic liquid or solid which contains the bivalent -0-0- structure and may be considered a derivative of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. The term also includes organic peroxide formulations (mixtures). Organic peroxides are thermally unstable substances and mixtures, which may:
    • Be liable to explosive decomposition;
    • Burn rapidly;
    • Be sensitive to impact or friction;
    • eact dangerously with other substances.
    Substances and mixtures of this hazard class are assigned to one of seven "Types A to G", on the basis of the results of specific tests36.
  • Corrosive to Metals37. A substance or a mixture which is corrosive to metal is one which by chemical action will materially damage, or even destroy, metals. These substances or mixtures are classified in a single hazard category on the basis of tests on steel or aluminum when the surface corrosion rate exceeds 6.25 mm per year at a test temperature of 55° C38.

GHS Health Hazards

The following ten health hazards have been defined by the GHS:
  • Acute Toxicity
  • Skin Corrosion/Irritation
  • Serious Eye Damage/Eye Irritation
  • Respiratory or Skin Sensitization
  • Germ Cell Mutagenicity
  • Carcinogenicity
  • Reproductive Toxicology
  • Specific Target Organ Toxicity - Single Exposure
  • Specific Target Organ Toxicity - Repeated Exposure
  • Aspiration Toxicity
Substances are classified on the basis of available data or test results. Mixtures, on the other hand, are classified by a tiered methodology:
  • Test data on the mixture
  • Bridging Principles (explained below)
  • Calculation methods. The particular calculation methods depend upon the specific health hazard endpoint and are found within the chapter covering each health hazard.
  • Acute Toxicity39. This GHS defines acute toxicity as those adverse effects occurring after oral or dermal administration of a single dose of a substance or mixture, or multiple doses given within 24 hours, or after an inhalation exposure or 4 hours. Substances are assigned to one of the five toxicity categories on the basis of LD50 (oral, dermal)40 or LC50 (inhalation)41. The LC50 values are based on 4-hour tests in animals. However, the GHS provides guidance on converting 1-hour inhalation test results to a 4-hour equivalent.
    Acute toxicity Cat. 1 Cat. 2 Cat. 3 Cat. 4 Category 5
    Oral (mg/kg) ≤ 5 > 5
    ≤ 50
    >50
    ≤ 300
    > 300
    ≤ 2000
    Criteria:
    • Anticipated oral LD50 between 2000 and 5000 mg/kg;
    • Indication of significant effect in humans;*
    • Any mortality at class 4;*
    • Significant clinical signs at class 4;*
    • Indications from other studies.*
    *If assignment to a more hazardous class is not warranted.
    Dermal (mg/kg) ≤ 5 > 5
    ≤ 200
    > 200
    ≤ 1000
    > 1000
    ≤ 2000
    Gases (ppm) ≤ 100 > 100
    ≤ 500
    > 500
    ≤ 2500
    > 2500
    ≤ 5000
    Vapors (mg/l) ≤ 0.5 > 0.5
    ≤ 2.0
    > 2
    ≤ 10
    > 10
    ≤ 20
    Dust & mists (mg/l) ≤ 0.05 > 0.05
    ≤ 0.5
    > 0.5
    ≤ 1.0
    > 1
    ≤ 5
    In the US, OSHA is only regulating Categories 1-4. Category 5 would be used for consumer products.
  • Skin Corrosion/Irritation42.
    • Skin Corrosion:The production of irreversible damage to the skin in at least 1 of 3 animals following the application of a test substance for up to 4 hours. Substances and mixtures in this hazard class are assigned to the single harmonized Category 1: Corrosive. In the case of transport, for example, this is further subdivided into Categories 1A, 1B, and 1C based upon the duration of the exposure, and allows assignment of the chemical or mixture into Packing Groups.
      To minimize animal testing, the GHS includes the following factors that should be evaluated beforehand and which can serve as the basis for classification:
      • Human experience showing irreversible damage to the skin;
      • Structure/activity or structure property relationship to a substance or mixture already classified as corrosive;
      • pH extremes of ≤ 2 and ≥ 11.5 including acid/alkali reserve capacity.
    • Irritation: The production of reversible damage to the skin following the application of a test substance for up to 4 hours. Chemicals or mixtures are assigned to Category 2 of this health hazard class if the Draize43 score is ≥ 2.3 but < 4.0 or if it causes persistent inflammation. Those whose Draize score is ≥ 1.5 but < 2.3 may be assigned to Category 3 (Mild Skin Irritation).
      As with corrosive substances, human experience and structure/activity relationships should be considered in determining the potential for irritation before testing is initiated.
  • Serious Eye Damage/Eye Irritation44.
    • Serious Eye Damage: The production of tissue damage in the eye, or serious physical decay of vision, following application of a test substance to the anterior (front) surface of the eye, which is not fully reversible within 21 days of application. Substances and mixtures in this hazard class are assigned to the single harmonized Category 1
    • Eye Irritation: Changes in the eye following the application of a test substance to the anterior (front) surface of the eye, which are fully reversible within 21 days of application. Chemicals or mixtures are assigned to a single harmonized Category 2. However, the GHS provides some flexibility as follows: if the effects are fully reversible within 21 days they can be differentiated into Sub-Category 2A, or Sub-Category 2B if the effects are reversible in 7 days.
      As with skin corrosion/irritation, the GHS includes the following factors that should be evaluated before initiating testing, and which can serve as the basis for classification:
      • Human or animal experience indicating that the chemical or mixture is corrosive or irritating to eyes or skin;
      • Structure/activity or structure property relationship to a substance or mixture already classified as corrosive or irritating to eyes or skin;
      • pH extremes of ≤ 2 and ≥ 11.5 including acid/alkali reserve capacity.
      Note that for the first two factors listed above, effects on skin are deemed sufficient for classifying effects on the eye.
  • Respiratory or Skin Sensitization45.
    • Respiratory sensitizer: A substance that induces hypersensitivity of the airways following inhalation of the substance. Substances and mixtures in this hazard class are assigned to Category 1. The GHS does permit differentiation into Sub-Categories 1A and 1B, depending upon:
      • Frequency of occurrence in humans
      • Probability of a high vs. low to moderate sensitization rate occurrence in humans based upon animal data
      • Severity of reaction.
    • Skin sensitizer: A substance that will induce an allergic response following skin contact. The definition for "skin sensitizer" is equivalent to "contact sensitizer". Substances and mixtures in this hazard class are assigned to Category 1. As with respiratory sensitizers, this hazard class can be further differentiated into two sub-categories, based upon factors similar to those presented immediately above
  • Germ Cell Mutagenicity46 Mutagen means a chemical or mixture that can cause mutations47 in the germ cells of humans that can be transmitted to their off-spring. . Substances and mixtures in this hazard class are assigned to one of two hazard categories. Category 1 has two subcategories:
    • Category 1A: Substances or mixtures known to induce heritable mutations. Assignment to this category is based upon human epidemiological studies.
    • Category 1B: Substance which should be regarded as if they induce heritable mutations in the germ cells of humans. Assignment to this category is based upon animal data, or human tests results that demonstrate mutagenic effects with no evidence of transmission to off-spring.
    Category 2 includes those substances which cause concern for humans owing to the possibility that they may induce heritable mutations in the germ cells of humans. Assignment to this category is based upon animal data, or in vitro tests.
  • Carcinogenicity48 Carcinogen means a chemical substance or a mixture of chemical substances which induce cancer or increase its incidence. Substances and mixtures in this hazard class are assigned to one of two hazard categories. Category 1 has two subcategories.
    • Category 1A: Substances or mixtures known to induce heritable mutations. Assignment to this category is based upon human epidemiological studies.
    • Category 1B: Substance which should be regarded as if they induce heritable mutations in the germ cells of humans. Assignment to this category is based upon animal data, or human tests results that demonstrate mutagenic effects with no evidence of transmission to off-spring.
    Category 2 includes those substances which cause concern for humans owing to the possibility that they may induce heritable mutations in the germ cells of humans. Assignment to this category is based upon animal data, or in vitro tests.
  • Reproductive Toxicity49 Reproductive toxicity includes adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in offspring. Substances and mixtures with reproductive and/or developmental effects are assigned to one of two hazard categories, "known or presumed" and “suspected.” Category 1 has two subcategories for reproductive and developmental effects.
    • Category 1A: Known human reproductive toxicant. A substance in placed in this category largely based on human evidence.
    • Category 1B: Presumed human reproductive toxicant. Assignment to this category is largely based on animal evidence.
    Category 2 Suspected human reproductive toxicant. There is evidence from humans or experimental animals, possibly supplemented with other data, for a substance or mixture assigned to this category, but which is not sufficiently convincing to place it in Category 1.
    Materials which cause concern for the health of breastfed children have a separate category, Effects on or Via Lactation.
  • Specific Target Organ Toxicity - Single Exposure50 Substances and mixture that cause specific, non-lethal target organ toxicity arising from a single exposure are assigned to this hazard class. All significant health effects that can impair function, reversible and irreversible, immediate and/or delayed are included, with exception of those effects already covered in other chapters of Part 3. Classification depends upon reliable evidence that a single exposure of a substance or mixture has produced a consistent and identifiable toxic effect in humans, or an effect in experimental animals that has relevance for humans. Human data are the primary sources of evidence. Specific target organ toxicity can occur by any route of exposure, principally, oral, dermal, or inhalation.
    This hazard class is divided into three categories.
    • Category 1: Substances that have produced significant toxicity in humans, or that, on the basis of evidence from studies in experimental animals can be presumed to have the potential to product significant toxicity in humans following a single exposure. Classification depends upon reliable evidence that a single exposure of a substance or mixture has produced a consistent and identifiable toxic effect in humans, or an effect in experimental animals at low doses that has relevance for humans.
    • Category 2: Substances that, on the basis of evidence from studies in experimental animals can be presumed to have the potential to be harmful to human health following a single exposure. Placing a substance or mixture in this category generally depends upon reliable evidence that a single exposure of a substance or mixture in experimental animals at moderate doses has produced significantly toxic effects that have relevance for humans.
    • Category 3: Transient target organ effects. This category only includes narcotic effects51 and respiratory tract irritation.
  • Specific Target Organ Toxicity - Repeated Exposure52 Substances and mixture that cause specific, non-lethal target organ toxicity arising from a repeated exposure are assigned to this hazard class. All significant health effects that can impair function, reversible and irreversible, immediate and/or delayed are included. As discussed above, those effects already covered in other chapters of Part 3 are excluded from this hazard class.
    This hazard class is divided into two categories.
    • Category 1: Substances that have produced significant toxicity in humans, or that, on the basis of evidence from studies in experimental animals can be presumed to have the potential to product significant toxicity in humans following repeated exposure. Assignment to this category depends upon reliable evidence in humans, or an effect in experimental animals at low doses that has relevance for humans.
    • Category 2: Substances that, on the basis of evidence from studies in experimental animals can be presumed to have the potential to be harmful to human health following repeated exposure. Assignment to this category generally depends upon reliable evidence that a repeated exposure of a substance or mixture in experimental animals at moderate doses has produced significantly toxic effects of relevance for humans.
  • Aspiration Hazard53 Aspiration is the entry of a substance or mixture, whether liquid or solid, directly through the oral or nasal cavity, or indirectly from vomiting, into the trachea and lower respiratory system. Aspiration toxicity includes severe acute effects such as chemical pneumonia, varying degrees of pulmonary injury or death following aspiration. This hazard class comprises two categories.
    • Category 1: Chemicals known to cause human aspiration toxicity hazards or to be regarded as if they cause human aspiration toxicity hazard. A chemical substance or mixture is assigned to this hazard class and category based upon reliable and good human evidence, or if it is a low viscosity hydrocarbon54.
    • Category 2: Chemicals which cause concern owing to the presumption that they cause human aspiration toxicity hazard. In assigning a chemical or mixture to this category, animal studies and expert judgment are used, and take into account surface tension, water solubility, boiling point, and volatility. Kinematic viscosity can also be an indicator for this category.

Bridging Principles55

As mentioned above in the introduction to the GHS Health Hazards, Bridging Principles are an important concept in the GHS for classifying untested mixtures. When a mixture has not been tested, but when there are sufficient data on both the individual components and similar tested mixtures to adequately characterize the hazards of the mixture, these data can be used in accordance with the bridging principles listed below. The use of bridging principles allows the maximum use of existing data and minimizes testing on animals.
  • Dilution: If a mixture is diluted with a diluent that has an equivalent or lower toxicity, then the hazards of the new mixture are assumed to be equivalent to the original.
  • Batching: If a batch of a complex substance is produced under a controlled process, then the hazards of the new batch are assumed to be equivalent to the previous batches.
  • Concentration of Highly Toxic Mixtures: If a batch of a complex substance is produced under a controlled process, then the hazards of the new batch are assumed to be equivalent to the previous batches.
  • Interpolation within One Toxic Category: Mixtures having component concentrations within a range where the hazards are known are assumed to have those known hazards.
  • Substantially Similar Mixtures: Slight changes in the concentrations of components are not expected to change the hazards of a mixture and substitutions involving toxicologically similar components are not expected to change the hazards of a mixture.
  • Aerosols: An aerosol form of a mixture is assumed to have the same hazards as the tested, non-aerosolized form of the mixture unless the propellant affects the hazards upon spraying.
All bridging principles do not apply to every health hazard class. A fuller explanation of the bridging principles that apply to the above health hazard classes is listed in each chapter of Part 3.

GHS Environmental Hazards

The GHS currently incorporates two environmental hazards for the following media: water and the ozone layer.

Dangerous to the Aquatic Environment56

The following four factors are used in classifying aquatic hazards for the GHS:
  • Acute (short term) aquatic toxicity
  • Chronic (long term) aquatic toxicity
  • Potential for or actual bioaccumulation
  • Degradation (biotic or abiotic) for organic chemicals.
  • Acute aquatic toxicity: The intrinsic property of a substance to harm an aquatic organism in a short-term exposure to it. The organisms typically tested are fish, crustacea, and algae since they are considered as surrogates for all aquatic organisms; other organisms may be considered. This hazard class is subdivided into three categories:
    Acute Category 1 L(E)C5057 ≤ 1.00 mg/l
    Acute Category 2 L(E)C50 > 1.00 but ≤ 10.0 mg/l
    Acute Category 3 L(E)C50 >10.0 but < 100 mg/l
  • Chronic aquatic toxicity: The intrinsic property of a substance to cause adverse effects to aquatic organisms during aquatic exposures which are determined in relation to the life-cycle of the organism. Chronic toxicity data are generally less available than acute data, and the test methods for determining it are less standardized. This hazard class is subdivided into three categories and a “safety net” category (Chronic Category 4). The latter is used when available data do not allow classification under the criteria, but there are still concerns.
    Classification follows a tiered approach: First, determine whether available data is adequate for classification as a chronic hazard. If so, then classify into either two or three Chronic Categories, depending upon the how readily the substance degrades in the aquatic environment.
    Chronic Category 1
    Chronic NOEC58 or ECx59 ≤ 0.1 mg/l Not rapidly degradable
    Chronic NOEC or ECx ≤ 0.01 mg/l Rapidly degradable
    Chronic Category 2
    Chronic NOEC or ECx ≤ 1 mg/l Not rapidly degradable
    Chronic NOEC or ECx ≤ 0.1 mg/l Rapidly degradable
    Chronic Category 3 Chronic NOEC or ECx ≤ 1 mg/l Rapidly degradable
    If adequate chronic data are not available, then classification is accomplished by using information on acute aquatic toxicity data and environmental fate data (bioaccumulation and biodegradability).
    Chronic Category 1
    Chronic NOEC58 or ECx59 ≤ 0.1 mg/l Not rapidly degradable
    Chronic NOEC or ECx ≤ 0.01 mg/l Rapidly degradable
    Chronic Category 2
    Chronic NOEC or ECx ≤ 1 mg/l Not rapidly degradable
    Chronic NOEC or ECx ≤ 0.1 mg/l Rapidly degradable
    Chronic Category 3 Chronic NOEC or ECx ≤ 1 mg/l Rapidly degradable
    Mixtures are classified by a tiered methodology similar to that discussed above for health hazards:
    • Test data on the mixture
    • Bridging Principles (explained above under GHS Health Hazards)
    • Calculation methods: “Summation of classified ingredients” and/or an “additivity formula.” These calculation methods are detailed in the chapter. It is noteworthy that the summation method utilizes "multiplying factors" that are applied to highly toxic ingredients classified as Acute or Chronic 1. The more toxic the ingredient, the more weight is assigned to it in the calculation.

Hazardous to the Ozone Layer62

This hazard class contains only one category. Substances are assigned to Category 1 if it is any of the controlled substances listed in Annexes to the Montreal Protocol. Any mixture containing ≥ 0.1% of at least one controlled substance is also classified as Category 1.

Labeling63

As shown in the Figure in the Introduction, the label for the same product can be different, depending upon the country in which it is sold. And even within a country, a label can look and read differently depending upon the market in which it is sold. One of the aims of the GHS was the development of harmonized hazard communication system, including labels, safety data sheets and comprehensible symbols. The GHS includes the appropriate labeling tools to convey information about each hazard class and category. The ILO, which was the working group assigned hazard communication, identified the following target audiences and the different needs of each:
  • Workplace
  • Consumers
  • Emergency Responders
  • Transport
Comprehensibility was a key issue addressed during their work, and they identified the following guiding principles:
  • Information should be conveyed in more than one way.
  • Comprehensibility studies, both existing and in the literature, must be considered.
  • The phrases used to indicate the degree of hazard should be consistent across all hazard classes. For example, flammability and carcinogenicity are very different hazard types, but a way needed to be found to put the degree of hazard into context and therefore convey the same degree of concern.
The following label elements have been standardized: symbols, signal words, statements of hazard, label format, and color. Precautionary statements have not yet been fully harmonized; however, the UN Purple Book provides guidance on the selection of appropriate statements in Annex 3.
The following is an example of a GHS label for Sneeze Right64 showing all of the required elements:
The following are the pictograms65 that have been harmonized in the GHS:
Explosives
Explosives Self Reactive Organic Peroxide
Gases Under Pressure
Gasses Under Pressure
Carcinogenicity
Carcinogenicity Respiratory Sensitizer Reproductive Toxicity Target Organ Toxicity Mutagenicity Aspiration Toxicity
Flamable
Flammable Self Reactive Pyrophoric Self-Heating Emits Flammable Gas Organic Peroxides
Skin Corrosion
Skin Corrosion Serious Damage to Eye Corrosive to Metals
Dermal Sensitizer
Skin & Eye Irritant Dermal Sensitizer Acute Toxicity Transient Target Organ Effects
Oxidizer
Oxidizers
Acute Toxicity
Acute Toxicity
Environmental Toxicity
Environmental Toxicity
The red border is part of the pictogram.
Standardization of labeling information has been accomplished by including in each chapter in parts 2, 3 and 4 a section on Hazard Communication that lists the required symbol, signal word, and hazard statement. In the case of a substance or mixture that belongs to more than one hazard class, these three hazard communication elements must be taken into account for each hazard class. This section on labeling provides guidance on such situations and on determining the precedence for symbols and hazard statements. In the case of signal words, "Danger" takes precedence, and "Warning" is not used.
Guidance is also provided for the label format. For example, the GHS requires that the hazard pictograms, signal word, and hazard statements be located together. There is also guidance on the labeling of small packages.
Section 3 of Annex 3 to the Purple Book is entitled "Use of Precautionary Statements," and includes general precautionary measures as well as tables of recommended precautionary statements for each hazard class and hazard category of the GHS. The tables also incorporate the other required hazard communication elements.
The following is a representative table for a substance or mixture classified as a flammable solid:

As you can see, the precautionary statements are grouped by type (Prevention, Response, etc.). Not every hazard class includes all of the types, as shown. When using these tables, it is important to refer to all of tables that apply. Thus, in the case of a substance or mixture that has more than one hazard, for example flammable solid and aspiration hazard, it will be necessary to refer to both tables to determine the required precautionary statements.

Safety Data Sheets66

The SDS is a comprehensive document that provides detailed information about a substance or mixture. The primary target audience for the SDS is the workplace, although it is useful for emergency responders and transport workers. Both employers and employees rely on the SDS to provide important information about the hazards of the substances and mixtures to which they are exposed, and about safety precautions they can take to assure their well-being. Although the label also provides hazard statements and precautionary measures, the very size of a label restricts how much information can be provided. Further, not every product is packaged in a container (i.e., bulk shipments), so a label is not available in all instances. But every product must have an accompanying SDS.
SDS are product specific but not workplace specific, so they generally are not able to provide information that is relevant for a particular workplace. However, employers can use the information in an SDS to tailor worker protection measures, including training, which are appropriate to her or his workplace. SDS also contain important environmental information that will allow the employer to establish measures to protect the environment.
The GHS mandates that an SDS be prepared for every substance or mixture that meets the criteria for a physical, health, or environmental hazard. Further, the GHS requires that an SDS be prepared for all mixtures which contain ingredients that meet the criteria for carcinogenic, toxic to reproduction, or specific target organ toxicity, provided the concentration of such ingredients exceed certain cut-off values, even if the mixture does not meet the criteria for a health hazard67.

SDS Format

A SDS prepared according to the GHS contains the following 16 sections, in the order shown:
1 Identification
  • GHS product identifier.
  • Other means of identification
  • Recommended use of the chemical and restrictions on use.
  • Supplier's details (including name, address, phone number, etc.).
  • e) Emergency phone number.
2 Hazard(s) identification
  • GHS classification of the substance/mixture and any national or regional information.
  • GHS label elements, including precautionary statements. (Hazard symbols may be provided as a graphical reproduction of the symbols in black and white or the name of the symbol, e.g., flame, skull and crossbones.)
  • Other hazards which do not result in classification (e.g., dust explosion hazard) or are not covered by the GHS.
3 Composition/information on ingredients Substance
  • Chemical identity.
  • Common name, synonyms, etc.
  • CAS number, EC number, etc.
  • Impurities and stabilizing additives which are themselves classified and which contribute to the classification of the substance.

Mixture
The chemical identity and concentration or concentration ranges of all ingredients which are hazardous within the meaning of the GHS and are present above their cutoff levels.

NOTE: For information on ingredients, the competent authority rules for CBI68 take priority over the rules for product identification.
4 First-aid measures
  • Description of necessary measures, subdivided according to the different routes of exposure, i.e., inhalation, skin and eye contact, and ingestion.
  • Most important symptoms/effects, acute and delayed.
  • Indication of immediate medical attention and special treatment needed, if necessary.
5 Fire-fighting measures
  • Suitable (and unsuitable) extinguishing media.
  • Specific hazards arising from the chemical (e.g., nature of any hazardous combustion products).
  • Special protective equipment and precautions for firefighters.
6 Accidental release measures
  • Personal precautions, protective equipment and emergency procedures.
  • Environmental precautions.
  • Methods and materials for containment and cleaning up.
7 Handling and storage
  • Precautions for safe handling.
  • Conditions for safe storage, including any incompatibilities.
8 Exposure controls/personal protection
  • Control parameters, e.g., occupational exposure limit values or biological limit values.
  • Appropriate engineering controls.
  • Individual protection measures, such as personal protective equipment.
9 Physical and chemical properties
  • Appearance (physical state, color, etc.).
  • Odor.
  • Odor threshold.
  • pH.
  • melting point/freezing point.
  • initial boiling point and boiling range.
  • flash point.
  • evaporation rate.
  • flammability (solid, gas).
  • upper/lower flammability or explosive limits.
  • vapor pressure.
  • vapor density.
  • relative density.
  • solubility(ies).
  • partition coefficient: n-octanol/water.
  • autoignition temperature.
  • decomposition temperature.
10 Stability and reactivity
  • Chemical stability.
  • Possibility of hazardous reactions.
  • Conditions to avoid (e.g., static discharge, shock or vibration).
  • Incompatible materials.
  • Hazardous decomposition products
11 Toxicological information Concise but complete and comprehensible description of the various toxicological (health) effects and the available data used to identify those effects, including:
  • information on the likely routes of exposure (inhalation, ingestion, skin and eye contact);
  • Symptoms related to the physical, chemical and toxicological characteristics;
  • Delayed and immediate effects and also chronic effects from short- and long-term exposure;
  • Numerical measures of toxicity (such as acute toxicity estimates).
12 Ecological information
  • Ecotoxicity (aquatic and terrestrial, where available).
  • Persistence and degradability.
  • Bioaccumulative potential.
  • Mobility in soil.
  • Other adverse effects.
13 Disposal considerations Description of waste residues and information on their safe handling and methods of disposal, including the disposal of any contaminated packaging.
14 Transport information
  • UN Number.
  • UN Proper shipping name.
  • Transport Hazard class(es).
  • Packing group, if applicable.
  • Environmental hazards (e.g., Marine pollutant (Yes/No).
  • Transport in bulk (according to Annex II of MARPOL. 73/78 and the IBC Code).
  • Special precautions which a user needs to be aware of or needs to comply with in connection with transport or conveyance either within or outside their premises.
15 Regulatory information Safety, health and environmental regulations specific for the product in question.
16 Other information
If specific information is not applicable or not available under one of the sub-headings, the SDS should clearly state this. Blanks are not permitted. If country specific information, such as permissible exposure limits, is included, the SDS should state the relevant country/region.
The GHS includes Annex 4, which provides guidance on preparing an SDS.

Highlights of the OSHA Final Rule

As mentioned above, OSHA issued a final rule on March 26, 2012 revising its Hazard Communication Standard to conform to the GHS. In this rule, OSHA changed certain terms to conform to the GHS. For example, hazards are now “classified”, not evaluated. A label is now:
  • An appropriate group of written, printed or graphic information elements concerning a hazardous chemical that is affixed to, printed on, or attached to the immediate container of a hazardous chemical, or to the outside packaging.
    rather than
    Any written, printed, or graphic material displayed on or affixed to containers of hazardous chemicals.
As noted earlier, the GHS is modular, consisting of “building blocks” that could be selected by countries and agencies in developing a specific hazard communication system. Accordingly, the OSHA rule includes all GHS physical hazard classes and categories, and all health hazard classes. However, the following health hazard categories are not regulated by OSHA:
  • Acute toxicity, Category 5
  • Corrosion/Irritation, Category 3
  • Aspiration toxicity, Category 2.
In addition, because OHSA’s mandate is the workplace, no environmental hazards are included.
Also, as mentioned previously, the GHS also allows countries to keep national requirements that it does not cover. Accordingly, the OSHA definition of a hazardous chemical is:
  • "Hazardous chemical" means any chemical which is classified as a physical hazard or a health hazard, a simple asphyxiant, combustible dust, pyrophoric gas, or hazard not otherwise classified.
Those hazards printed in bold are not in the universe of hazards listed in Parts 2-3 of the GHS, but are being regulated by OSHA. Hazard Not Otherwise Classified (HNOC) means an adverse physical or health effect identified through evaluation of scientific evidence that does not meet the specified criteria for classification (in other words, it has not been identified in the GHS as a physical or health hazard). This category does not include those hazards that:
  • Fall below the cut-off value/concentration limit of a hazard class; or,
  • Fall under a GHS hazard category that has not been adopted by OSHA (e.g., acute toxicity Category 5).
Another significant change relates to the manner in which a mixture is classified. Under the “old” OSHA Hazard Communication Standard, a mixture was classified as hazardous if it contains more that 1% of an ingredient that is classified as hazardous, or 0.1% in the case of a carcinogen. Under the “new” rule, there are specific criteria for each hazard class.
An SDS for HNOC chemicals is required and information regarding their hazards must be included in Section 2.
The following are some highlights of the OSHA rule:
  • Hazards are classified, not evaluated.
  • Classification criteria are revised
  • Labeling provisions are revised to include standardized:
    • Signal words
    • Pictograms
    • Hazard statements
    • Precautionary statements
  • Labels must be updated in 6 months
  • "Floor" of hazardous chemicals is removed69.
  • The "one study" rule is revised70.
  • The 1% and 0.1% mixture rules are eliminated71.
  • The Appendices are replaced and/or revised.
With regard to safety data sheets, the following are still required on the SDS
    • ACGIH TLVs
    • Information regarding carcinogenicity classifications by IARC and NTP
    • Hazard statements
    • Precautionary statements
1 The term "chemical" is broad under the Globally Harmonized System and includes substances, products, mixtures, preparations, or any other terms that may be used by existing systems.
2 The Canadian label also requires a specific hashed border which is not shown, and the text must be in English and Canadian French.
3 The European label must be in the language of the country where it is being sold.
4 However, the European Union's regulations also cover consumer chemicals, so the label would be identical for a consumer product.
5 The United Nations Recommendation on the Transport of Dangerous goods covers the transport sector, and is maintained by the United Nations Subcommittee of Experts on the Transportation of Dangerous Goods.
6 The book has a purple cover; it is available from the United Nations bookstore. It is identified as ST/SG.AC.10/30/Rev. 4
7 See the United Nations website for the current status of implementation: http://www.unece.org/trans/danger/publi/ghs/implementation_e.html
8 Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006
9 "Update on GHS in Canada," Canadian Centre for Occupational Health and Safety podcast released May 25, 2012 http://www.ccohs.ca/products/podcasts/
11 For example, the revised OSHA Hazard Communication Standard, 29 CFR 1910.1200, includes combustible dust.
12 Part 2, Chapter 2.1.
13 The following US OSHA definition is referenced in the Purple Book: "Article means a manufactured item other than a fluid or particle: (i) which is formed to a specific shape or design during manufacture; (ii) which has end use function(s) dependent in whole or in part upon its shape or design during end use; and (iii) which under normal conditions of use does not release more than very small quantities, e.g., minute or trace amounts of a hazardous chemical …, and does not pose a physical hazard or health risk to employees." (29 CFR 1910.1200).
14 Part 2, chapter 2.2
15 Part 2, chapter 2.3
16 Part 2, chapter 2.4
17 Part 2, chapter 2.5
18 Part 2, chapter 2.6
19 Part 2, chapter 2.7
20 UN Test N.1 (UN Manual of Tests and Criteria)
21 Part 2, chapter 2.8
22 UN Test Series A to H (UN Manual of Tests and Criteria)
23 Part 2, chapter 2.9
24 UN Test N.3 (UN Manual of Tests and Criteria)
25 Part 2, chapter 2.10
26 UN Test N.2 (UN Manual of Tests and Criteria)
27 Part 2, chapter 2.11
28 UN Test N.4 (UN Manual of Tests and Criteria)
29 Part 2, chapter 2.12
30 UN Test N.5 (UN Manual of Tests and Criteria)
31 Part 2, chapter 2.13
32 UN Test 0.2 (UN Manual of Tests and Criteria)
33 Part 2, chapter 2.14
34 UN Test 0.1 (UN Manual of Tests and Criteria)
35 Part 2, chapter 2.15
36 UN Test Series A to H (UN Manual of Tests and Criteria)
37 Part 2, chapter 2.16
38 UN Test in Part III, subsection 37.4 (UN Manual of Tests and Criteria)
39 Part 3, chapter 3.1
40 LD50 - The oral or dermal dose that causes death in 50% of test animals.
41 LC50 - The concentration of a substance in air that will kill 50% of test animals within a certain exposure period.
42 Part 3, chapter 3.2
43 See OECD Guideline 404 for the methodology and scoring.
44 Part 3, chapter 3.3
45 Part 3, chapter 3.4
46 Part 3, chapter 3.5
47 A mutation is defined as a permanent change in the amount or structure of the genetic material in a cell.
48 Part 3, chapter 3.6
49 Part 3, chapter 3.7
50 Part 3, chapter 3.8
51 Narcotic effects include central nervous system depression, drowsiness, narcosis, reduced alertness, loss of reflexes, lack of coordination and vertigo. They can also include severe headache or nausea, and can lead to reduced judgment, dizziness, irritability, fatigue, impaired memory function, deficits in perception and coordination, reaction time, or sleepiness.
52 Part 3, chapter 3.9
53 Part 3, chapter 3.10
54 Specific viscosity criteria are listed in Table 3.10.1 of Part 3.
55 Part 3, chapter 3.1.3.5
56 Part 4, chapter 4.1
57 LC50 - The concentration of a substance in water that will kill 50% of test animals within a certain exposure period, which is usually 96 hours for fish.
EC50 – The effective concentration of a substance that causes 50% of the maximum response within a certain exposure period, which is 48 hours for crustacea, and either 72 or 96 hours for algae.
58 No observed effect concentration. The NOEC has no statistically significant adverse effect compared to the control.
59 ECX – The effective concentration of a substance that causes x% response.
60 Logarithm of the Oil/Water partition coefficient
61 Bioconcentration factor
62 Part 4, chapter 4.2
63 Part 1, chapter 1.4
64 See page 2 for current US and Canadian labels.
65 A pictogram contains the symbol and the border.
66 Part 1, chapter 1.5
67 Table 1.5.1
68 Confidential Business Information. See Part 1, chapter 1.4.8.1
69 According to the "old" OSHA Hazard Communication Standard, The chemical manufacturer, importer or employer evaluating chemicals must treat the following sources as establishing that the chemicals listed in them are hazardous: (i) 29 CFR part 1910, subpart Z, Toxic and Hazardous Substances, Occupational Safety and Health Administration (OSHA); or, (ii) Threshold Limit Values for Chemical Substances and Physical Agents in the Work Environment, American Conference of Governmental Industrial Hygienists (ACGIH) (latest edition).
70 Under the "old" rule one positive study conducted in accordance with established scientific principles, and which reports statistically significant findings regarding the carcinogenic potential of the substance is sufficient for classification. Under the “new” OSHA rule, such findings do not automatically form the basis for classification, but must be noted on the safety data sheet.
71 The GHS tiered approach to mixtures is incorporated into the HCS:
  • Use available test data on the mixture as a whole
  • Use bridging principles to extrapolate data
  • Use cut--‐offs based on the known hazards of ingredients
    • The GHS gives competent authorities a choice of cut-­‐offs for chronic effects; OSHA chose the lower of those available for the various effects

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