American Chemical Society (ACS) Laboratory Safety Practice Test 2025 – All-in-One Guide to Mastering Lab Safety Procedures!

The definition of permissible exposure limit (PEL) specifically refers to the maximum concentration of a substance to which workers can be exposed over a specified period, usually an 8-hour workday. This limit is established to protect workers' health and ensure a safe working environment. A PEL is intended to set a threshold that is considered safe for an employee's daily exposure, taking into account the risk of health effects that can arise from inhalation or contact with hazardous substances.

This definition is grounded in the recognition that while certain substances may be unavoidable in the workplace, there are established levels of exposure that can minimize risks to health. The PEL is used by regulatory agencies, such as the Occupational Safety and Health Administration (OSHA), to guide safety measures and compliance in various industries.

The other choices do not capture the essence of the PEL. For instance, while one may think about emergency responders or laboratory settings, those do not accurately describe the broader application and intent of PEL as it is universally applicable to worker safety regarding exposure levels.