How Does Haz-Map Handle Information from Animal Toxicology and Medical Toxicology?

For occupational cancers, Haz-Map follows IARC in the way it synthesizes animal and epidemiological data. For acute occupational diseases, animal data is sufficient if the routes of entry correspond. Examples of such acute occupational diseases include poisoning by pesticides, solvents, simple asphyxiation, hydrofluoric acid, and toxic pneumonitis.

In Haz-Map, there is a distinction between adverse effects (includes animal toxicology and human poisonings by ingestion cases) and occupational diseases (cases of workers made ill after inhalation or skin absorption). Thus, for six conditions in Haz-Map (hepatotoxicity, methemoglobinemia, peripheral neuropathy, hemolytic anemia, chemical asphyxiation, and aplastic anemia) each chemical is linked to either the adverse effect, the adverse effect and the disease, or neither. For example, hydrogen cyanide causes chemical asphyxiation in both animal experiments and workplace accidents. Hydrogen cyanide is linked to both the adverse effect and the disease. Copper is a reported cause of hemolytic anemia after ingestion (linked to adverse effect) but not after occupational exposure (not linked to occupational disease).

“Serious limitations of toxicologic studies include differences between species and routes of exposure. For example, gavage (tube feeding) differs greatly from the routes by which patients typically have been exposed. In addition, animal studies almost invariably depend on use of relatively high doses of single toxins, and invariably require extrapolation to be applicable to clinical situation.” [Rosenstock, p. 40]

“Animal cancer tests, which are done at the maximum tolerated dose (MTD), are being misinterpreted to mean that low doses of synthetic chemicals and industrial pollutants are relevant to human cancer. About half of the chemicals tested, whether synthetic or natural, are carcinogenic to rodents at these high doses. A plausible explanation for the high frequency of positive results is that testing at the MTD frequently can cause chronic cell killing and consequent cell replacement, a risk factor for cancer that can be limited to high doses. Ignoring this greatly exaggerates risks.” [Ames BN, 1998, PMID 9677052]

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Revised: May 30, 2018

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