The OSHA Globally Harmonized System (GHS) standard is capable of reducing the quantity and quality of information on hazardous chemicals to which American workers are exposed. The standard may bring the United States into conformity with international standards established under the auspices of the United Nations, but GHS is likely to be most helpful to employers in the U.S. and abroad as well as multinational corporations, rather than U.S. workers. Problems with GHS include:
Elimination of the principle, central to the Hazard Communication standard (HazCom) that one good positive toxicology or epidemiology study is sufficient to classify a chemical as hazardous. The “weight of the evidence” principle central to GHS could allow negative studies judged adequate by companies preparing labels/SDS (safety data sheets, the GHS terminology for MSDS) to justify failure to classify a chemical as hazardous.
Under GHS, chemicals known to cause cancer or other severe toxicity in humans could be labeled or described as “may cause” cancer rather than “cause cancer.” This represents a significant weakening of warning language.
Toxicity descriptions for chemical constituents of mixtures could be weakened, since mixtures will be considered as a whole, rather than chemical-by-chemical.
GHS sets out reasons for not classifying chemicals as hazardous. Principles from both classical and mechanistic toxicology are used to downgrade concerns about chemical hazards. The downgrades reflect industry viewpoints represented by the members of the science advisory committee for the U.N. GHS effort.
If OSHA standards are primarily intended to help U.S. workers, GHS is very much in need of major revisions.