Some regulatory agency; in the US, this is likely the Environmental Protection Agency (EPA) or the Occupational Safety and Health Administration (OSHA), though other agencies (such as the Food and Drug Administration or Department of Agriculture) might stick their noses in also.
Permissible exposure limits are levels of exposures permitted by OSHA, the US Occupational Safety and Health Administration.
Permissible exposure limits are levels of exposures mandated by:
OSHA
exposure to high levels of fallout a single exposure to high-energy radiation repeated exposures to both high energy radiation and high levels of fallout
- exposure to high levels of fallout - single exposure to high energy radiation - repeated exposures to both high energy radiation and high levels of fallout
repeated exposures to both high-energy radiation and high levels of fallout a single exposure to high-energy radiation exposure to high levels of fallout
repeated exposures to both high-energy radiation and high levels of fallout exposure to high levels of fallout a single exposure to high-energy radiation
A single exposure to high-energy radiation exposure to high levels of fallout repaeted exposures to both high-energy radiation and high levels of fallout
MCUs are a type of polyurethane that is used to coat wood floors in homes. They make a very durable and scratch resistant finish and are often used on gymnasium and bowling alley floors. Exposure to MCU chemicals can lead to health effects depending on the level and duration of exposure. Brief exposures to elevated levels can result in headaches, respiratory irritation, and exacerbation of asthma; while very high and/or long-term (e.g. lifetime) exposures can lead to more serious health effects.
black holes
Permissible Exposure Limits (PELs) are maximum permitted exposure levels established by the US Occupational Safety and Health Administration (OSHA).
"The health effects resulting from most chlorine exposures begin within seconds to minutes. The severity of the signs and symptoms caused by chlorine will vary according to amount, route and duration of exposure. Inhalation: Most chlorine exposures occur via inhalation. Low level exposures to chlorine in air will cause eye/skin/airway irritation, sore throat and cough. Chlorine's odor provides adequate early warning of its presence, but also causes olfactory fatigue or adaptation, reducing awareness of one's prolonged exposure at low concentrations. At higher levels of exposure, signs and symptoms may progress to chest tightness, wheezing, dyspnea, and bronchospasm. Severe exposures may result in noncardiogenic pulmonary edema, which may be delayed for several hours. Ingestion: Since chlorine is a gas at room temperature, it is unlikely that a severe exposure will result from ingestion. However, ingestion of chlorine dissolved in water (e.g., sodium hypochlorite or household bleach) will cause corrosive tissue damage of the gastrointestinal tract. Eye/Dermal Contact: Low level exposures to chlorine gas will cause eye and skin irritation. Higher exposures may result in severe chemical burns or ulcerations. Exposure to compressed liquid chlorine may cause frostbite of the skin and eyes." as seen on http://www.health.state.ny.us/environmental/emergency/chemical_terrorism/chlorine_tech.htm