The original classifications for health hazard criteria for the GHS were developed by the Organization for Economic Cooperation and Development (OECD). The classifications for physical hazard criteria were originally developed by the United Nations Committee of Experts on the Transportation of Dangerous Goods. The hazard communication methods such as labels and safety data sheets were originally developed by the International Labor Organization. Although OSHA made numerous changes in reaching its new HCS regulations, the knowledge and methods of the original preparers still benefit the final work product.
Product Liability Law Obligations to Warn
Over five decades ago, courts throughout the United States began to change prior law to allow product purchasers (and eventually others) to sue not only their sellers but everyone else in the supply chain, such as distributors and manufacturers, and even designers, parts suppliers, and raw material suppliers (Spence v. Three Rivers Builders, 353 Mich. 120,
Omitting earlier antecedents, it has been almost five decades since the courts decided to impose strict liability without fault on product sellers, distributors, manufacturers, designers and suppliers (Greenman v. Yuba Power Products, Inc.,
In product liability cases, plaintiff attorneys regularly allege “failure to warn” claims that may prevail even when there is no design defect or manufacturing defect. The requirement to warn about foreseeable uses and misuses is difficult to defend because manufacturers of chemicals and other products generally do not have regular access to the daily operations of their customers, who typically regard their operations as confidential. The limited knowledge manufacturers have about customer operations may be overrated by juries, who have a human tendency to use hindsight when evaluating foreseeability.
Recognizing that it can be very difficult or impossible for manufacturers of chemicals and other industrial products to provide warnings directly to their customers’ employees, the courts in some states recognized defenses to the failure to warn allegations. The defenses are commonly called the “bulk supplier defense,” the “sophisticated user defense,” and the “sophisticated intermediary defense.” It is those defenses that allow manufacturers to provide warnings to their customers by means such as labels and safety data sheets rather than attempt to deliver the warnings directly to customer employees. However, the defenses may be lost if a manufacturer provides inadequate warnings or provides warnings to customers who should not be relied upon to furnish the warnings to their employees (Taylor v. American Chemistry Council,
.,
Manufacturers often defend allegations of misdesign, mismanufacture or failure to warn by introducing evidence to show that their products met applicable government and industry standards for each of those elements. In response, the courts generally allow plaintiff attorneys to present evidence that the applicable government or industry standards were only minimum requirements and inadequate to overcome evidence of mismanufacture, misdesign or failure to warn. In recent years, government and industry standards have become increasingly more extensive and strict, but it remains to be seen how much weight the courts and legislatures will give to compliance with them. Recent decisions include Jablonski v. Ford Motor Co.,
For example, proponents and opponents of the model Regulatory Compliance Congruity With Liability Act (MRCCLA) sponsored by the American Legislative Exchange Council are contesting whether it should be adopted by state legislatures. Briefly, the MRCCLA is a model law that presents to state legislatures two options that could excuse product liability if a manufacturer or seller meets the requirements of federal or state law or a government agency. If adopted, Option 1 provides that the manufacturer or seller would not be subject to liability if it meets the requirements. Option 2 provides a rebuttable presumption that the manufacturer or seller would not be subject to liability if it meets the requirements.
In its announcement of the new HCS regulations in the Federal Register, OSHA said that they do not preempt state tort failure to warn lawsuits and cited Lindsey v. Caterpillar, Inc.,
When the courts began to develop the law of product liability, the author remembers managers across the chemical industry wondering how to provide warnings to customers, customers’ employees, and other users of their products. Thus, the development of the original HCS was significant for the chemical industry and the many other industries that used its products. The labeling, material safety data sheet, and other requirements of the HCS provided practical and government-recognized means to communicate through customers to customer employees and others.
Some HCS Fundamentals That Did Not Change
The expanded HCS continues to require manufacturers and importers to evaluate their chemical products and provides extensive and detailed requirements for doing so. It also continues not to require them to test chemicals. This is not surprising because the HCS is a communications standard and not a program like those administered by the Environmental Protection Agency under the Toxic Substances Control Act (TSCA). Under TSCA, EPA has been authorized and required for over three decades to perform a premanufacturing review (including test data) of all new chemicals to be manufactured or imported into the United States. EPA also can (and does) order testing of chemicals “grandfathered” from the premanufacture review requirements by inclusion in its TSCA Inventory because they were manufactured, imported or processed for commercial use in the United States between Jan. 1, 1975, and July 1, 1979.
The new HCS continues to apply to any chemical that is known to be present in the workplace in such a manner that employees may be exposed under normal conditions of use or in a foreseeable emergency.
The expanded HCS does not require employers who do not produce or import chemicals to perform the chemical hazard evaluation and classification required of manufacturers and importers. It expressly states that those employers are not required to classify chemicals unless they choose not to rely on the classification performed by the chemical manufacturer or importer. They need only focus on the parts of the HCS that deal with establishing a workplace program and communication of information to their workers. That is consistent with court-developed product liability law, which places product responsibilities on manufacturers and others in the product supplier chain. Further, employers provide workers’ compensation benefits to their employees and, with some exceptions, are protected from liability to their employees by state workers’ compensation laws.
The expanded HCS continues to require distributors to assure that containers are properly labeled, tagged or marked and to deliver safety data sheets. Distributors are not subject to the duties to evaluate chemicals that are required of manufacturers and importers.
The expanded HCS continues to require not only manufacturers and importers but also distributors and employers who become aware of significant new information regarding the hazards of a chemical to revise the labels for the chemical, but the period to do so has been extended from three months to nine months.
The expanded HCS continues to focus on worker health and safety rather than broader environmental objectives. For example, the new HCS does not require evaluation of potential hazards to air or water quality or to animals and plants. However, the improved hazard communications resulting from the new HCS will provide valuable information that can be used to protect the environment.
Much-Expanded Health Hazard, Physical Criteria
Appendix A (Health Hazards Criteria) and Appendix B (Physical Criteria) contain the key provisions of the expanded HCS. Although not required to test their chemicals, manufacturers and importers are required to evaluate and classify their hazards. The two appendices provide in a relatively few pages not only definitions, requirements, and criteria but also extensive information such as references to test methods and data that must or may be used to evaluate chemical hazards. For example, the referenced test methods range from well-known acute toxicity tests LD50 (oral, dermal) and LC50 (inhalation) to costly in vivo heritable germ cell mutagenicity tests such as the rodent dominant lethal mutation test (OECD 478) and the mouse heritable translocation assay (OECD 485). Sources of data and other information include the American Council of Government Industrial Hygienists (ACGIH), the International Agency for Research on Cancer (IARC), and the National Toxicology Program (NTP).
OSHA’s definitions of the 10 health hazards and 16 physical hazards listed in Appendices A and B are shown in Exhibit A at the end of this article. Brief descriptions of the classification criteria that OSHA required and the test methods OSHA referenced in Appendices A and B are shown in Exhibit B to this article.
In the introduction to the Health Hazard Criteria, OSHA provided general classification considerations that are of fundamental importance. The term “hazard classification” is used to indicate that only the intrinsic hazardous properties of chemicals are considered. The consideration consists of three steps: (a) identification of relevant data regarding the hazards of a chemical; (b) subsequent review of those data to ascertain the hazards associated with the chemical; and (c) determination of whether the chemical will be classified as hazardous and the degree of hazard.
The general classification considerations add that the criteria for determining health hazards are test method neutral, i.e., they do not specify particular test methods, as long as the methods are scientifically validated, a term that OSHA discusses in detail. Existing data are acceptable for classifying chemicals, although expert judgment also may be needed.
Significantly, the general classification conditions say that the effect of a chemical on the biological system is influenced by the physico-chemical properties of the substance and/or ingredients of a mixture and the way in which ingredient substances are biologically available. A chemical need not be classified when it can be shown by conclusive experimental data from scientifically validated test methods that the chemical is not biologically available. Further, for classification purposes, epidemiological data and experience on the effects of chemicals on humans (e.g., occupational data, data from accident databases) must be taken into account in the evaluation of human health hazards of a chemical.
Described briefly, OSHA states that classification shall be based on the weight of the evidence. All information shall be considered, including valid in vitro tests, relevant animal data, and human experience such as epidemiological and clinical studies and well-documented case reports and observations. Quality and consistency of data and both positive and negative results shall be considered together. Reliable, good quality human data shall generally have precedence over other data. Positive results from well-conducted animal studies are not necessarily negated by lack of positive human experience but require an assessment of the robustness, quality and statistical power of both the human and animal data. However, a single positive study performed according to good scientific principles and with statistically and biologically significant positive results may justify classification.
Again briefly, OSHA says that route of exposure, mechanistic information, and metabolism studies are pertinent to determining the effect in humans. They may demonstrate that a mechanism or mode of action is not relevant to humans or raise doubt about relevance. If not relevant, a chemical should not be classified. If there is doubt, a lower classification may be warranted.
For most hazard classes, OSHA recommended a process of classification of mixtures in a sequence: (a) where test data are available for the complete mixture, the classification will always be based on those data; (b) where test data are not available for the mixture itself, bridging principles designated in each chapter of Appendices shall be considered; and (c) if test data are not available for the mixture itself and available information is not sufficient to use the bridging principles, than cut-off values and concentration limits based on the information known will be applied. As an exception, however, classification of mixtures for carcinogenicity, germ cell mutagenicity and reproductive toxicity shall be based upon information on the ingredient substance unless justification can be provided for classifying based on the mixture as a whole.
The result of the classification process is a determination that a chemical need not be classified or that it should be placed in a classification and a category and perhaps a subcategory of the classification. For some hazards such as skin corrosion and irritation, OSHA prescribed a tiered evaluation and provided a diagram illustrating the method.
Some OSHA Decisions That Were Opposed
Although some commenters questioned its decision, OSHA included a “hazard not otherwise classified” in the definition of a “hazardous chemical.” OSHA also included a definition of “hazard not otherwise classified.” If a manufacturer or exporter identifies a hazard not otherwise identified, it must evaluate and classify the hazard like the hazards for which OSHA established classifications.
OSHA also decided to include a “simple asphyxiant” in the definition of a “hazardous chemical” notwithstanding a comment that it should not be covered because it is not an inherent toxicity. OSHA defined a “simple asphyxiant” to mean “a substance or mixture that displaces oxygen in the ambient atmosphere, and can thus cause oxygen deprivation in those who are exposed, leading to unconsciousness and death.” In support of its decision, OSHA said that not every chemical has these properties, so the asphyxiation hazard is inherent and chemical-dependent.
OSHA also decided notwithstanding opposition to include “combustible dust” in the definition of a hazardous chemical, but did not provide a definition of “combustible dust.” OSHA’s decision recognizes the real and severe hazards of combustible dusts, but leaves a quandary for chemical manufacturers and importers. Some of the most severe explosions and fires involving combustible dusts have involved seemingly harmless substances such as grains, sugar, and chewing gum, and control of risk is largely in the hands of the customer using a chemical or other substance. In discussing its decision, OSHA observed that not all dusts in the workplace are combustible, and processing them does not always result in combustible atmospheres. OSHA added that it had provided guidance in its Hazard Communication Guidance for Combustible Dusts (OSHA 3371-08, 2009) and its Combustible Dust National Emphasis National Program Directive (C
Some of OSHA’s decisions that were opposed have been challenged by petitions to the U.S. Court of Appeals for the District of Columbia Circuit. The petitions did not challenge the new HCS as a whole.
Potential Effects of Expanded HCS
The expanded HCS should significantly improve the quantity and quality of communications to employers, workers, and others about the health and physical hazards of chemicals. Although time will tell on the actual results, it should result in significant reductions of illnesses and injuries. The results should begin to appear in the OSHA Form 300 injury logs of employers across the United States.
For years, some small and medium-sized manufacturers and importers believed that they could comply with the HCS by saying in material safety data sheets (MSDSs) that no information was available, although they had made only a limited search. Some prepared “me too” MSDSs by borrowing answers from MSDSs of large companies, although the chemical products might not be entirely the same. The additional specific requirements and helpful information in the expanded HCS should clarify to small and medium-sized manufacturers and importers that they must and can achieve compliance. In return, they will benefit from the use of a global system and greater confidence that their products will be used safely.
It is difficult to predict whether compliance with the expanded requirements of the new HCS will provide protection from product liability. Plaintiff attorneys can and will read the new HCS and the volumes of materials that led to its adoption. They could, for example, make a number of failure to warn claims against manufacturers and importers:
1. Failure to perform the evaluation required by the HCS.
2. Inadequate performance of the evaluation required by the HCS.
3. Failure to adequately disclose data or other information obtained from an evaluation in a label and/or safety data sheet.
4. Failure to test a chemical, even though the HCS does not require testing.
5. Failure to go beyond the scope of the HCS based on an argument that the expanded HCS requirements should be treated as only minimum duties.
Plaintiff attorneys could make failure to warn claims against distributors for failure to assure that chemical containers are properly labeled and safety data sheets are delivered to customer employers. Plaintiff attorneys could also claim that a distributor has the same duties to evaluate chemical hazards as manufacturers and importers, especially if a large distributor is selling chemicals produced by a small domestic manufacturer or a foreign manufacturer that has little or no experience doing business in the United States. Some distributors address this risk by requiring manufacturers to agree to defend and indemnify them against product liability and by requiring manufacturers to arrange for their product liability insurers to name them by endorsement as additional insureds.
Chemical manufacturers and importers can justifiably say that the new HCS is far more comprehensive than the prior HCS, especially because of the inclusion of hazards not otherwise classified. However, the author of this article believes that most courts and state legislatures are unlikely to treat compliance with the new HCS as more than a defense against liability that can be rebutted. Thus, the author recommends that chemical manufacturers and importers make identification and classification of possible hazards not otherwise classified an important part of their compliance programs. That is likely to mean undertaking the task of reaching out to customers to learn more about how they use (and might misuse) their chemical products in order to provide effective warnings.
EXHIBIT A: HEALTH AND PHYSICAL HAZARD CRITERIA DEFINITIONS
A. Health Hazard Definitions
A.1. Acute toxicity refers to those adverse effects occurring following oral or dermal administration of a single dose of a substance, or multiple doses given within 24 hours, or an inhalation exposure of 4 hours.
A.2. Skin corrosion is the production of irreversible damage to the skin; namely, visible necrosis through the epidermis and into the dermis, following the application of a test substance for up to 4 hours.
A.3. Serious eye damage is the production of tissue damage in the eye, or serious physical decay of vision, following application of a test substance to the anterior surface of the eye, which is not fully reversible within 21 days of application. Eye irritation is the production of changes in the eye following the application of test substance to the anterior surface of the eye, which are fully reversible within 21 days of application.
A.4. Respiratory sensitizer means a chemical that will lead to hypersensitivity of the airways following inhalation of the chemical. Skin sensitizer means a chemical that will lead to an allergic response following skin contact.
A.5. A mutation is defined as a permanent change in the amount or structure of the genetic material in a cell. The term mutation applies both to heritable genetic changes that may be manifested at the phenotypic level and to the underlying DNA modifications when known (including, for example, specific base pair changes and chromosomal translocations). The term mutagenic and mutagen will be used for agents giving rise to an increased occurrence of mutations in populations of cells and/or organisms.
A.6. Carcinogen means a substance or a mixture of substances which induce cancer or increase its incidence. Substances and mixtures which have induced benign and malignant tumors in well-performed experimental studies on animals are considered also to be presumed or suspected human carcinogens unless there is strong evidence that the mechanism of tumor formation is not relevant for humans.
A.7. Reproductive toxicity includes adverse effects on sexual function and fertility in adult males and females, as well as adverse effects on development of the offspring. Some reproductive toxic effects cannot be clearly assigned to either impairment of sexual function and fertility or to developmental toxicity. Nonetheless, chemicals with these effects shall be classified as reproductive toxicants.
A.8. Specific target organ toxicity—single exposure, (STOT-SE) means specific non-lethal target organ toxicity arising from a single exposure to a chemical. All significant health effects that can impair function, both reversible and irreversible, immediate and/or delayed and not specifically addressed in A.1 to A.7 and A.10 of this Appendix are included.
A.9. Specific target organ toxicity—repeated exposure (STOT-RE) means specific target organ toxicity arising from repeated exposure to a substance or mixture. All significant health effects that can impair function, both reversible and irreversible, immediate and/or delayed and not specifically addressed in A.1 to A.7 and A.10 of this Appendix are included.
A.10. Aspiration means the entry of a liquid or solid chemical 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.
B. Physical Hazard Definitions
B.1. An explosive chemical is a solid or liquid chemical 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 chemicals are included even when they do not evolve gases. A pyrotechnic chemical is a chemical 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.
B.2. Flammable gas means a gas having a flammable range with air at 20 C (68 F) and a standard pressure of 101.3 kPa (14.7 psi).
B.3. Aerosol means any non-refillable receptacle containing a gas compressed, liquefied or dissolved under pressure, and fitted with a release device allowing the contents to be ejected as particles in suspension in a gas, or as a foam, paste, powder, liquid or gas. Aerosols shall be considered for classification as flammable if they contain any component which is classified as flammable in accordance with this appendix i.e.,: Flammable liquids (See B.6); Flammable gases (See B.2); Flammable solids (See B.7).
B.4. Oxidizing gas means any gas which may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does. NOTE. “Gases which cause or contribute to the combustion of other material more than air does” means pure gases or gas mixtures with an oxidizing power greater than 23.5% (as determined by a method specified in ISO 10156 or 10156-2 (incorporated by reference, See §1910.6 or an equivalent testing method.)
B.5. Gases under pressure are gases which are contained in a receptacle at a pressure of 200 kPa (29 psi) (gauge) or more, or which are liquefied or liquefied and refrigerated. They comprise compressed gases, liquefied gases, dissolved gases and refrigerated liquefied gases.
B.6. Flammable liquid means a liquid having a flash point of not more than 93 C (199.4 F). Flash point means the minimum temperature at which a liquid gives off vapor in sufficient concentration to form an ignitable mixture with air near the surface of the liquid, as determined by a method identified in Section B.6.3.
B.7. Flammable solid means a solid which is a readily combustible solid, or which may cause or contribute to fire through friction. Readily combustible solids are powdered, granular, or pasty chemicals 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.
B.8. Self reactive chemicals are thermally unstable liquid or solid chemicals liable to undergo a strongly exothermic decomposition even without participation of oxygen (air). This definition excludes chemicals classified under this section as explosives, organic peroxides, oxidizing liquids or oxidizing solids. A self-reactive chemical is regarded as possessing explosive properties when in laboratory testing the formulation is liable to detonate, to deflagrate rapidly or to show a violent effect when heated under confinement.
B.9. Pyrophoric liquid means a liquid which, even in small quantities, is liable to ignite within five minutes after coming into contact with air.
B.10. Pyrophoric solid means a solid which, even in small quantities, is liable to ignite within five minutes after coming into contact with air.
B.11. A self-heating chemical is a solid or liquid chemical, other than a pyrophoric liquid or solid, which, by reaction with air and without energy supply, is liable to self-heat; this chemical differs from a pyrophoric liquid or solid in that it will ignite only when in large amounts (kilograms) and after long periods of time (hours, or days). NOTE: Self-heating of a substance or mixture is a process where the gradual reaction of that substance or mixture with oxygen (in air) generates heat. If the rate of heat production exceeds the rate of heat loss, then the temperature of the substance or mixture will rise which, after an induction time, may lead to self-ignition and combustion.
B.12. Chemicals which, in contact with water, emit flammable gases are solid or liquid chemicals which, by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities.
B.13. Oxidizing liquid means a liquid which, while in itself not necessarily combustible, may, generally by yielding oxygen, cause, or contribute to, the combustion of other material.
B.14. Oxidizing solid means a solid which, while in itself is not necessarily combustible, may, generally by yielding oxygen, cause, or contribute to, the combustion of other material.
B.15. Organic peroxide means a liquid or solid organic chemical which contains the bivalent-0-0-structure and as such is considered a derivative of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. The term organic peroxide includes organic peroxide mixtures containing at least one organic peroxide. Organic peroxides are thermally unstable chemicals, which may undergo exothermic self-accelerating decomposition. In addition, they may have one or more of the following properties: (a) be liable to explosive decomposition; (b) burn rapidly; (c) be sensitive to impact or friction; and (d) react dangerously with other substances.
B.16. A chemical which is corrosive to metals means a chemical which by chemical action will materially damage, or even destroy, metals.
EXHIBIT B: CLASSIFICATION CRITERIA AND TEST METHODS PRESCRIBED BY APPENDICES A AND B
Appendices A and B require manufacturers and importers to classify each chemical by obtaining and evaluating existing data on its health and physical hazards. They are not required to test their chemicals, but may do so if they wish. In general, the classification criteria require that the classifier first consider human evidence, including epidemiological studies, and then information from other sources including tests using experimental animals such as rats and mice. The tests must be scientifically validated.
Appendices A and B go well beyond the former HCS in providing classification criteria which state the requirements and also provide references to test methods which must or may be used to classify chemicals. The following paragraphs briefly describe the classification criteria and tests which OSHA requires or references.
A.1 Acute toxicity is classified (A) by using data from tests which administer to rats a single dose of the chemical and measure the dose or concentration which is lethal to 50% of the rat population or (B) by using acute toxicity estimate (ATE) values based on existing data. The lethal dose is called LD50 and applies to oral and dermal exposure. The lethal concentration is called LC50 and applies to inhalation exposure to gases, vapors, dusts and mists. A vapor is a gas released from a liquid or solid. A mist consists of liquid droplets suspended in air or some other gas. Author’s Note: LC50 and LD50 values can be obtained from sources such as the Registry of Toxic Effects of Chemical Substances (RTECS).
A.2 Skin corrosion or irritation shall be classified by using a tiered approach. Emphasis shall be placed upon existing human data followed by information from other sources. In vitro alternatives that have been scientifically validated shall also be used to make validation decisions. The data may include results from tests which administer a chemical to the skin of animals such as rats and rabbits by applying a dose using means such as a patch. Skin irritation may also be classified by using data from tests which administer a chemical to humans in ethically conducted tests. A chemical can also be classified as corrosive based on extremes such as pH 2 ≤ (acid) or ≥ 11.5 (caustic). Test results may be based on observations of ulcers, bleeding, bloody scabs and, after 14 days, discoloration due to skin blanching, complete areas of alopecia, and scabs. Reversibility of these conditions, normally within 14 days, is the difference between skin corrosion and skin irritation. OSHA’s examples of scientifically validated test methods include OECD IG 430 (Transcutaneous Electrical Resistance Tests), OECD TG 431 (Human Skin Model Test), and OECD TG 435 (Membrane Barrier Test Method). A scientifically validated in vitro test for skin irritation is OECD TG 439 (Reconstructed Human Epidermis Test Method).
A.3 Serious eye damage or irritation shall be classified in a tiered approach beginning with existing human data followed by existing animal data including data from tests which administer a chemical to the anterior surface of the eye of an animal and observation of effects on the cornea (opacity), iris (iritis) and/or conjunctiva (redness or edema). Reversibility normally within 21 days is the difference between serious eye damage and eye irritation. Test methods specifically mentioned are the Draize eye test with rabbits, OECD TG 437 (Bovine Corneal Opacity and Permeability) and OECD TG 438 (Isolated Chicken Eye). Measurement of pH alone ( ≤ 2.0 or ≥ 11.5) may be adequate, but assessment of acid or alkali reserve (buffering capacity) is preferable.
A.4 Respiratory or skin sensitization can normally be justified based on effects seen in either humans or animals including epidemiological studies and studies which expose experimental animals to a chemical. Sensitization consists of a first phase induction of a specialized immunological memory by exposure and a second phase elicitation of a cell or antibody-mediated allergic response. OSHA stated that recognized and validated animal models for the testing of respiratory hypersensitivity are not available. However, OSHA described human evidence and animal studies that may indicate respiratory sensitization. For skin sensitization, human evidence may include a human repeat insult patch test, a human maximization test, strong diagnostic patch test data, and epidemiological evidence. Animal tests may include OECD Guideline 406 (Guinea Pig Maximization Test), OECD guideline 429 (Local Lymph Node Assay) and a screening test called the Mouse Ear Swelling Test. Author’s Note: During its discussion in the Federal Register, OSHA used toluene diisocyanate (TDI) as an example of a sensitizer at very small concentrations. OSHA added that, once an individual is sensitized, a response can be triggered at even lower levels than those initially required to induce sensitization.
A.5 Germ cell mutagenicity is classified by considering test results from experiments determining mutagenic and/or genotoxic effects in germ and/or somatic cells of exposed animals, i.e., in vivo tests using laboratory animals to determine whether a chemical induces heritable mutations in germ cells or DNA modifications such as base pair changes and chromosomal transactions. Results of in
vitro tests may also be considered. OSHA considers a mutagen to be an agent which gives rise to increased mutations in populations of cells and/or organisms. OSHA said that genotoxicity tests are usually taken as indicators for mutagenic effects. OSHA provided numerous examples of scientifically validated test methods:
1. In vivo heritable germ cell mutagenicity:
(a) Rodent dominant lethal mutation test (OECD 478)
(b) Mouse heritable translocation assay (OECD 485)
2. In vivo somatic cell mutagenicity:
(a) Mammalian bone marrow chromosome aberration test (OECD 475)
(b) Mouse spot test (OECED 484)
(c) Mammalian erythrocyte micronucleus test (OECED 474)
3. Mutagenicity/genotoxicity tests in germ cells:
(a) Mutagenicity tests:
(b) Mammalian spermatogonial chromosome aberration test (OECD 483)
(c) Spermatid micronucleus assay
(d) Genotoxicity tests
(e) Sister chromatic exchange analysis in spermatogonia
(f) Unscheduled DNA synthesis test (UDS) in testicular cells
4. Genotoxicity tests in somatic cells:
(a) Liver Unscheduled DNA Synthesis (UDS) in vivo (OECD) 486
(b) Mammalian bone marrow Sister Chromatid Exchanges (SCE)
5. In vitro mutagenicity:
(a) In vitro mammalian chromosome aberration test (OECD 473)
(b) In vitro mammalian cell gene mutation test (OECD 476)
(c) Bacterial reverse mutation tests (OECD 471)
6. New scientifically validated tests as they arise
Author’s Note. The author has worked with some of these tests which are difficult and costly. A manufacturer must have high confidence that a chemical will be successful because it can take years to recover the testing costs.
A.6 Carcinogenicity is classified by considering the strength and weight of human epidemiological and/or animal data. Some factors include (a) tumor type and background incidence; (b) multisite responses; (c) progression of lesions to malignancy; (d) reduced tumor latency; (e) whether responses are in single or both sexes; (f) whether responses are in a single species or several species; (g) structural similarity or not to a substance for which there is good evidence of carcinogenicity; (h) routes of exposure; (i) comparison of absorption, distribution, metabolism and excretion between test animals and humans; (j) possible confounding effect of excessive toxicity of test doses; and (k) mode of action and its relevance for humans such as mutagenicity, cytotoxicity with growth stimuolation, mitogenesis and immunosuppression. OSHA referred to guidelines developed by the International Agency for Research on Cancer which are attached to the regulations as Appendix F. The guidelines are identified in Appendix F as IARC’s Monographs on the Evaluation of Carcinogenic Risks in Humans (2006) and the Report on Carcinogens by the National Toxicology Program (NTP). Neither Appendix A nor Appendix F identifies specific tests, but they prescribe extensive guidance on the evaluation of data resulting from tests.
A.7 Reproductive toxicity shall be classified using human evidence and animal studies of the effects of a chemical on sexual function and fertility. The evidence may include epidemiological studies of humans and sub-chronic, chronic and special studies of animals. OSHA said that a number of scientifically validated test methods are available such as OECD Test Guideline 414, ICH Guideline SSA, 1993, ICH SSB, 1995, and one or two generation toxicity testing methods such as OECD Test Guidelines 415 and 416 OSHA added that results from screening tests can be used to justify classification such as OECD Guidelines 421 (Reproduction/Developmental Toxicity Screening Test) and 422 (Repeated Dose Toxicity Study with Reproduction/Development Toxicity Screening Test).
A.8 For specific target organ toxicity-single exposure, classification is initially based on reliable and good quality evidence from human cases or epidemiological studies and observations from studies of experimental animals in which significant and/or severe effects of relevance to human health were produced at generally low exposure concentrations. OSHA provided guidance values for several exposures, i.e., oral (rat), dermal (rat or rabbit), gas inhalation (rat), vapor inhalation (rat), and dust/mist/fume inhalation (rat). OSHA did not require or identify specific test methods and even said that there are currently no scientifically validated animal tests that deal specifically with respiratory tract irritation (RTI). However, OSHA discussed generally a broad range of information sources such as evidence from human cases; epidemiological studies; and observations from experimental studies of animals. OSHA also mentioned judgment-based extrapolation from a structural analogue previously classified.
A.9 Specific target organ toxicity—repeat or prolonged exposure classification is initially based on reliable and good quality evidence from human cases or epidemiological studies and observations from studies experimental animals in which significant and/or severe effects of relevance to human health were produced at generally low exposure concentrations. The studies include standard animal studies in rats or mice that are 28 day, 90 day or lifetime studies (up to 2 years) that include hematological, clinico-chemical and detailed macroscopic and microscopic examination to enable the toxic effects on target tissues or organ to be identified. OSHA provided guidance values to assist in category classifications applicable to a 90 day study, i.e., oral (rat), dermal (rat or rabbit), gas inhalation (rat), vapor inhalation (rat), and dust/mist/fume (rat). OSHA did not require or identify specific test methods. Author’s Note: The lifetime of rats and mice used in laboratory studies is about two years.
A.10 Aspiration hazard is a hazard identified by OSHA (and others) as the entry of a liquid or solid chemical 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 and varying degrees of pulmonary injury or death following aspiration. OSHA did not identify specific tests for aspiration hazard.
B.1 Explosives can be classified in accordance with the three step procedure in Part I of UN ST.SG/AC 10. See
B.2 Flammable gases are to be classified by tests which provide information described by OSHA which did not specify test methods.
B.3 Flammable aerosols can be classified as flammable if they contain any component classified as flammable including flammable liquids, gases and solids. Flammable aerosols do not include pyrophoric, self-heating or water-reactive chemicals. They are also not within the scope of flammable gases, flammable liquids or flammable solids. OSHA references heat of combustion tests such as ASTM D240-2, ISO 13943 and National Fire Protection Association (NFPA) 30-B.
B.4 Oxidizing gases can be classified in accordance with tests or calculation methods described in International Standards Organization (ISO) 10156-2.
B.5 Gases under pressure are classified by using tests which measure other pressure and critical temperature. OSHA did not require, or recommend, any specific test methods.
B.6 Flammable liquids are classified by determining their flash points. OHSA specified that flash points be determined in accordance with ASTM D56-05, ASTM D3278, ASTM D93-08 or any other method specified in GHS, Revision 3, Chapter 2.6. Initial boiling points shall be determined in accordance with ASTM D86-07a or ASTM D1078. Author’s Note: The regulations allow a choice between Pensky-Martens and Tagliabue testers, but prescribe closed testers.
B.7 Flammable solids which are powered, granular or pasty chemicals shall be classified when the time of burning of one or more of the test runs, performed in accordance with the test method described in UN ST/STG/AC.10, Part III, sub-section 33.2.1, is less than 45 seconds or the rate of burning is more than 2 mm/second (0.0866 inches/second). Powders of metals or solid metal alloys shall be classified as flammable solids when they can be ignited and the reaction spreads over the whole length of the sample in 10 minutes or less.
B.8 For purposes of classification, the properties of self-reactive chemicals shall be determined in accordance with test series A to H as described in Part II of the UN ST/SG/AC.10, Part II, section 28.* Self-accelerating decomposition temperature (SADT) shall also be determined in accordance with UN/ST/SG/AC.10, Part II, section 28. See
B.9 A pyrophoric liquid shall be classified using test N.3 in Part III, sub-section 33.3.1.5 of the UN ST/SC/AC.10* in accordance with Table B.9.1 See
B.10 A pyrophoric solid shall be classified using test N.2 in Part III, sub-section 33.3.1.4 of the UN ST/SG/AC.10* in accordance with Table B.10.1. See
B.11 A self-heating chemical shall be classified using test method N.4 in Part III, sub-section 33.3.3.6 of the UN ST/SC/AC.10* See
B.12 Chemicals which, in contact with water, emit flammable gases shall be classified using test N.5 in Part III, sub-section 33.4.1.4 of the UN ST/SG/AC.10.* See
B.13 An oxidizing liquid shall be classified using test 0.2 in Part III, sub-section 34.4.2 of the UN ST/SG/AC.10* in accordance with Table B.13.1. See
B.14 An oxidizing solid shall be classified using test 0.1 in Part III, sub-section 34.4.1 of the UN ST/SG/AC.10* in accordance with Table B.14.1. See
B.15 For purposes of classification, properties of organic peroxides shall be determined in accordance with test series A to H as described in Part II of the UN ST/SG/AC.10.* See
B.16 A chemical which is corrosive to metals shall be classified using the test in Part III, sub-section 37.4 of the UN ST/SG/AC.10* in accordance with Table B.16.1. See
* References to UN ST/SG/AC.10 are to the UN Manual of Tests and Criteria by the Committee of Experts on the Transport of Dangerous Goods.
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