Acute toxicity describes the adverse effects of a substance that result either from a single exposure or from multiple exposures in a short period of time (usually less than 24 hours). To be described as acute toxicity, the adverse effects should occur within 14 days of the administration of the substance.
Measures of acute toxicity
Regulatory values
Limits for short-term exposure, such as STELs or CVs, are defined only if there is a particular acute toxicity associated with a substance. These limits are set by the American Conference of Governmental Industrial Hygienists (ACGIH) and the Occupational Safety and Health Administration (OSHA), based on experimental data. The values set by these organizations do not always coincide exactly, and in the chemical industry it is general practice to choose the most conservative value in order to ensure the safety of employees. The values can typically be found in a material safety data sheet. There are also different values based on the method of entry of the compound (oral, dermal, or inhalation).
- Threshold limit value-time-weighted-average: The maximum concentration to which a worker can be exposed every work day (8 hours) and experience no adverse health effects.
- Ceiling value, CV or Threshold limit value-ceiling, TLV-C: The concentration which no person should ever be exposed to.