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Acute Exposure Guideline Levels (AEGLs) set levels of chemical concentration that pose a defined level of risk to humans (the general population, including susceptible individuals). [ 1 ] [ 2 ] [ 3 ] These levels are used in preventing and responding to disasters .
The MATC can be applied to the results of an acute toxicity test to obtain a concentration that would protect against adverse effects during an acute exposure. An LC 50 , or the concentration at which 50% of the organisms die during an acute toxicity test is used to derive a value called the acute to chronic ratio (ACR).
Many gases have toxic properties, which are often assessed using the LC 50 (median lethal concentration) measure. In the United States, many of these gases have been assigned an NFPA 704 health rating of 4 (may be fatal) or 3 (may cause serious or permanent injury), and/or exposure limits (TLV, TWA/PEL, STEL, or REL) determined by the ACGIH professional association.
There are three levels of PAC value (1 to 3) where each successive value is associated with an increasingly severe effect from a higher level of exposure. Each level is defined as follows: PAC-1 : Mild, transient health effects. PAC-2 : Irreversible or other serious health effects that could impair the ability to take protective action.
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 ...
For example, the EPA set an acute RfD for children of 0.0015 mg/kg/day for the organochlorine insecticide endosulfan, based on neurological effects observed in test animals. The EPA then looked at dietary exposure to endosulfan, and found that for the most exposed 0.1 % of children age 1–6, their daily consumption of the endosulfan exceeded ...
In 40 CFR 156.62, the EPA established four Toxicity Categories for acute hazards of pesticide products, with "Category I" being the highest toxicity category (toxicity class). Most human hazard, precautionary statements, and human personal protective equipment statements are based upon the Toxicity Category of the pesticide product as sold or ...
Threshold limit value − time-weighted average (TLV-TWA): The average exposure on the basis of a 8 hours per day, 40 hours per week work schedule. Threshold limit value − short-term exposure limit (TLV-STEL): A 15-minute TWA exposure that should not be exceeded at any time during a workday, even if the 8-hour TWA is within the TLV-TWA.