The National Toxicology Program [19,20] conducted a 28-day dietary range-finding study with pure PCP (20-270 mg/kg bw per day, approximately 99% pure, containing tetrachlorophenol as a single impurity) in F344 rats.
Pentachlorophenol and tetrachlorophenol dissolved in fats are adsorbed by skin in 62% and 63% respectively.
Many studies confirms these effects: groups of male and female F344 rats were given diets that contained 0, 200, 400 or 600 ppm PCP (approximately 99% pure with one impurity, tetrachlorophenol) in the diet (equivalent to doses of 0, 10, 20 or 30 mg/kg/day) for 105 weeks .
Sodium salts of pentachlorophenol (PCP) and tetrachlorophenol (TeCP) have been used extensively as fungicides in the lumber industry since the 1950s.
In addition, few studies have provided results specifically for pentachlorophenol or tetrachlorophenol, all with relatively small numbers of exposed people .
The new criteria essentially concern requirements regarding assessment and verification, maximum concentrations in final products of residues of certain toxic substances (chromium, arsenic, cadmium, lead, etc.), the use of certain harmful substances (pentachlorophenol (PCP), tetrachlorophenol
(TCP) as well as their salts and esters) and emissions produced during the manufacture of articles (waste water).
For 40 to 50 years, up to 1988, lumber manufacturers used water-soluble chlorophenates (usually sodium pentachlorophenol or sodium tetrachlorophenol
) to protect lumber from sapstain.
and pentachlorophenol were identified in agricultural products like carrots, potatoes and turnips in concentrations of 1 to 45 [micro]g/kg of wet weight  Chlorophenols were also determined in poultry with concentrations of 2 to 3 [micro]g/kg of chicken flesh.
All males employed for at least 1 year between 1 January 1950 and 31 December 1985 in 1 of 11 large softwood lumber mills that used the sodium salts of penta- and tetrachlorophenol
, hereafter referred to as chlorophenates, were included in the cohort (n = 23,829).