Where is it Commonly Found?
Tricresyl phosphate (TCP) is used as a fire retardant and plasticizer in polyvinyl chloride, polystyrene, and nitrocellulose, as an air filter medium, in solvent mixtures and waterproofing applications (Sax and Lewis 1987).
TCP is a neurotoxin and has chronic organ and reproductive toxicity in animals. Male rats had reduced sperm concentration and motility when treated with TCP at 200 mg/kg. Female rats treated with TCP exhibited a “dose-dependent cytoplasmic alteration of ovarian interstitial cells and increased numbers of follicles and corpora lutea” (Carlton et al., 1987).
A subcommittee of the National Research Council cited an earlier IPCS conclusion that “there is no safe level of ingestion for TCP, and that exposure through inhalation or dermal contact should be minimized” (NRC, 2000). Early studies on rabbits showed that commercial TCP in low doses produced ataxia and tremors, followed by death (Sjögren et al, 2010). There were degenerative changes to the brain, liver, and kidney in the rabbits that died. TCP causes skin irritation, neurotoxicity, reproductive and development toxicity. The tri-ortho-isomer of TCP (TOCP) has been associated with 60,000 cases of worldwide poisoning. A worker exposed to TCP for two and a half years suffered abdominal pain and diarrhea and was unable to stand without support. A year later after admission, he was completely recovered. It is established that for humans, ingestion of TCP results in delayed neurotoxicity, but absorption via skin and inhalation needs further studies.
TCP is mainly released into the environment from volatilization from plastics and leaking hydraulic fluids (HSDB 2003).
Commercial TCP is a mixture of 28 components, mainly containing TMCP and TPCP and also mixed tricresyl and dicresyl phosphates (NTP 2011; Sjögren et al, 2010). The National Toxicology Program of the US National Library of Medicine is currently conducting research on TCP (NTP 2011).
How is it Categorized?
Tricresyl phosphate, or TCP, is an organophosphate compound most commonly used as a plasticizer and was in fact one of the earliest commerical plasticizers for PVC. Although commercial samples are typically yellow, the compound is a colourless, viscous liquid. Like other Phosphate plasticizers, TCP imparts flame retardence and fungus resistance, even when used in amounts as low as 5% of the total plasticizer content.
What are its Synonyms?
FOSFATO DE TRICRESILO (DOT SPANISH)
IMOL S 140
NISSAN UNFLAME TCP
O-TOLYLPHOSPHATE PHOSPHORIC ACID
PHOSPHATE DE TRICRÉSYLE (DOT FRENCH)
PHOSPHORIC ACID TRICRESYL ESTER
PHOSPHORIC ACID, TRI-O-CRESYL ETHER
PHOSPHORIC ACID, TRI-O-TOLYL ESTER
PHOSPHORIC ACID, TRIS(2-METHYLPHENYL) ESTER
PHOSPHORIC ACID, TRITOLYL ESTER
TRICRESYL PHOSPHATE (<1% ORTHO ISOMER)
TRICRESYL PHOSPHATE (>= 1% ORTHO ISOMER)
TRI-O-CRESYL ESTER OF PHOSPHORIC ACID
TRI-O-TOLYL ESTER PHOSPHORIC ACID