Naphthenic acid agents, thickening agent of napalm and oil drying agents used in painting and wood surface treatment. Industrially useful naphthenates include those of aluminium, magnesium, calcium, barium, cobalt, copper, lead, manganese, nickel, vanadium, and zinc. One oft-cited study stated that "naphthenic acids are the most significant environmental contaminants resulting from petroleum extraction from oil sands deposits." However "under worst-case exposure conditions, acute toxicity is unlikely in wild mammals exposed to naphthenic acids in AOS tailings pond water, but repeated exposure may have adverse health effects." Naphthenic acids are present in Athabasca oil sands (AOL) tailings pond water (TPW) at an estimated
4-Methylcyclohexanemethanol carboxylic acids, which in the case of MCHM is 4-methylcyclohexanecarboxylic acid (CAS 13064-83-0), a naphthenic acid. The toxicity and environmental properties of these naphthenic acids have been well studied recently due to their occurrence as a major contaminant in water used for extraction of oil from tar sands. Naphthenic acids have both acute and chronic toxicity to fish and other organisms. The methyl ester of this acid is also listed as one of the major impurities in the "crude MCHM" as supplied by Eastman. The closely related compound cyclohexanedimethanol (CAS 105-08-8) exhibits low toxicity (3.5 g/kg) when fed orally to