Which statement correctly distinguishes TLV and PEL and their use in exposure assessment?

• A. TLV is an OSHA-enforceable limit; PEL is an ACGIH guideline.
• B. TLV is an ACGIH guideline and PEL is an OSHA-enforceable limit; both define target airborne concentrations used to assess exposures, guide monitoring strategies, and justify controls.
• C. TLV and PEL are interchangeable terms.
• D. TLV is a guideline for exposure monitoring; PEL is enforceable limits.

Answer: (B)

The main idea is that TLVs and PELs serve different levels of authority and purpose in exposure assessment. TLV is an ACGIH guideline—a recommended target that helps professionals judge whether worker exposures are within a reasonable range and guides decisions to reduce risk. PEL is an OSHA-enforceable limit—a legal maximum that employers must not exceed, with regulatory requirements and potential penalties if violated. In exposure assessment, both provide reference points to compare actual worker exposures, inform how monitoring should be conducted (what concentrations to measure, how often, and over what duration), and justify controls (engineering controls, administrative changes, or PPE) to keep exposures at safe levels. The key distinction is that TLVs are guidelines aimed at risk reduction and best practices, while PELs are legally enforceable limits. The other statements either mix up enforceability and guideline status, claim they’re interchangeable, or omit the regulatory versus guidance distinction.