Tricresyl Phosphate (Environmental Health Criteria Series)

Evaluates risks to human health and the environment posed by the production and use of tricresyl phosphate. Tricresyl phosphate is used in industry as a plasticizer in vinyl plastic manufacture, as a flame-retardant, as a solvent for nitrocellulose, in cellulosic molding compositions, and in the manufacture of fire-resistant hydraulic fluids and lubricants.
Because of the physico-chemical properties of tricresyl phosphate and its rapid biodegradation, the report concludes that use of the compound does not threaten the environment, though there is some evidence that crop plants can be affected by tri-o-cresyl phosphate released from plastic coverings. A section devoted to kinetics and metabolism concentrates on mechanisms of absorption, distribution, metabolism, and elimination that can help explain the well-documented neuropathic actions of tricresyl phosphate and, most notably, its highly toxic isomer, tri-o-cresyl phosphate.
The most extensive section assesses findings from toxicity studies, emphasizing the large number of studies documenting neurotoxic effects, often at very low doses. These effects are further characterized through a review of the numerous reported cases of large-scale human poisoning following the ingestion of accidentally or deliberately contaminated medicines and foodstuffs. Readers are given detailed information on the clinical symptoms of poisoning, the characteristics of delayed neuropathy, long-term prognosis, and advice on the first-aid treatment of victims. While the concluding section notes that use of tricresyl phosphate poses very little risk to either the environment or the general population, the report underscores the severity and long-duration of the neuropathology caused by accidental poisoning, noting that some victims never recover.