Acute toxicity

Any poisonous effect produced within a short period of time following an exposure, usually 24 to 96 hours. The ability of a substance to cause severe biological harm or death soon after a single exposure or dose. Also, any poisonous effect resulting from a single short-term exposure to a toxic substance. Adverse health effects from a single dose or exposure to a toxic chemical or other toxic substance. Acute toxicity is assessed using observations of accidental human exposures or by conducting LD50 tests on experimental animals, usually rodents.

http://www.epa.gov/OCEPAterms/aterms.html

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