Pentachlorophenol

Pentachlorophenol was once one of the most widely used biocides
in the United States, but it is now a restricted use pesticide
and is no longer available to the general public. It was
primarily used as a wood preservative. Pentachlorophenol is
extremely toxic to humans from acute (short-term) ingestion and
inhalation exposure. Acute inhalation exposures in humans have
resulted in neurological, blood, and liver effects, and eye
irritation. Chronic (long-term) exposure to pentachlorophenol by
inhalation in humans has resulted in effects on the respiratory
tract, blood, kidney, liver, immune system, eyes, nose, and skin.
Human studies are inconclusive regarding pentachlorophenol
exposure and reproductive effects. Human studies suggest an
association between exposure to pentachlorophenol and cancer.
Oral animal studies have reported increases in liver tumors and
two uncommon tumor types. EPA has classified pentachlorophenol
as a Group B2, probable human carcinogen.