2. A general obligation to measure hazardous chemical agents and CMRs

Depending on the chemical agent, occupational exposure limit values may be set in the form of VLEP-8H or VLCT :

• Occupational exposure limit values-8h (OELV-8h) are designed to protect the medium- and long-term health of workers exposed to a chemical agent over a working lifetime (chronic poisoning). They represent the time-weighted average concentration of a chemical agent in the air of a worker's respiratory zone over the course of an 8-hour working day.

• Short-term exposure limit values (STELVs or STELVs) are designed to protect workers against the toxic effects of a chemical agent due to exposure peaks (irritation phenomena, for example). It is a limit value corresponding to exposure measured over a reference period of 15 minutes during the exposure peak, whatever its duration.