Distinguish between an OSHA PEL and an ACGIH TLV in terms of enforceability and typical use in exposure assessment.

• A. PEL is legally enforceable; TLV is guidance used for risk assessment and control planning when PELs are not set or protective.
• B. PEL is guidance; TLV is legally enforceable.
• C. Both are legally enforceable.
• D. TLV replaces PEL when PEL is absent.

Answer: (A)

The key idea is the difference between enforceability and how they’re used in practice. OSHA PELs are legally enforceable exposure limits set by the agency; if workers’ exposures exceed a PEL, OSHA can take enforcement action. ACGIH TLVs, on the other hand, are guidelines or recommendations published by the American Conference of Governmental Hygienists. They aren’t legally enforceable by OSHA, but they serve as benchmarks for risk assessment and control planning.

In exposure assessment, TLVs are used to evaluate how current exposures stack up against a protective target and to guide the selection and prioritization of controls, especially when there isn’t a PEL or when a more protective target is desired. PELs establish what is legally permissible and drive compliance actions, whereas TLVs provide a professional standard for evaluating risk and informing engineering and administrative controls.