When must a respirator be worn according to OSHA standards?

A respirator must be worn when airborne levels may exceed the OSHA Permissible Exposure Limit (PEL) because this standard is set to protect workers from inhaling hazardous substances that can lead to serious health issues. The OSHA PEL is a regulatory limit on the amount or concentration of a substance in the air, and exceeding these levels indicates a potential risk of exposure that necessitates the use of respiratory protection.

This requirement is grounded in ensuring worker safety; when there is a possibility that the exposure to harmful substances, such as asbestos, could surpass permissible limits, respirators play a crucial role in providing a barrier against harmful inhalation. It's vital for employers to conduct monitoring and assessments of air quality to determine when respirators are necessary, ensuring compliance with safety standards and protecting the health of employees.

In contrast, the other scenarios do not necessitate respirator use based on established OSHA guidelines, as general activities like moving materials or taking breaks do not inherently increase the risk of exposure to hazardous airborne levels, nor is the use of respiratory protection solely at the discretion of a supervisor without regard to actual exposure risks.