Chemical hazard regulations and TLV concepts MCQs With Answer

Chemical hazard regulations and TLV concepts MCQs With Answer

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This quiz collection on Chemical Hazard Regulations and TLV Concepts is designed specifically for M.Pharm students preparing for advanced coursework and professional practice. It covers regulatory frameworks (OSHA, REACH, TSCA, GHS), exposure limits (TLV, PEL, REL, STEL, Ceiling, IDLH), biological monitoring (BEI), and practical concepts such as mixture additivity, ppm–mg/m3 conversions, and Safety Data Sheet (SDS) requirements. Questions mix conceptual understanding, regulatory distinctions, and calculation-based problems to reinforce safe handling, risk assessment, and compliance. Use these MCQs to test and deepen your grasp of hazard communication and occupational exposure management essential for pharmaceutical research, manufacturing, and laboratory safety.

Q1. What is the Threshold Limit Value (TLV) as defined by ACGIH?

  • A legally enforceable exposure limit set by the government
  • A guideline airborne concentration published by ACGIH below which nearly all workers may be repeatedly exposed without adverse effects
  • The concentration that will cause immediate incapacitation
  • An environmental air quality standard for outdoor pollution

Correct Answer: A guideline airborne concentration published by ACGIH below which nearly all workers may be repeatedly exposed without adverse effects

Q2. Which agency in the United States is primarily responsible for promulgating Permissible Exposure Limits (PELs)?

  • ACGIH (American Conference of Governmental Industrial Hygienists)
  • EPA (Environmental Protection Agency)
  • OSHA (Occupational Safety and Health Administration)
  • NIOSH (National Institute for Occupational Safety and Health)

Correct Answer: OSHA (Occupational Safety and Health Administration)

Q3. What does a Short-Term Exposure Limit (STEL) represent?

  • The maximum allowable concentration averaged over an 8-hour work shift
  • The concentration that should never be exceeded even momentarily
  • The acceptable average concentration for a 15-minute exposure period that should not be exceeded at any time during the workday
  • The biological concentration measured in blood or urine

Correct Answer: The acceptable average concentration for a 15-minute exposure period that should not be exceeded at any time during the workday

Q4. What does a “ceiling” occupational exposure limit mean?

  • An averaged limit over 8 hours
  • A concentration that should never be exceeded at any time during exposure
  • A recommended control technology for ventilation
  • The concentration associated with chronic effects only

Correct Answer: A concentration that should never be exceeded at any time during exposure

Q5. IDLH is an important emergency planning value. What does IDLH stand for?

  • Immediate Danger to Life or Health
  • Immediate Danger to Life and Health
  • Immediately Dangerous to Life or Health
  • Instant Danger to Life or Health

Correct Answer: Immediately Dangerous to Life or Health

Q6. Which organization publishes TLVs and Biological Exposure Indices (BEIs)?

  • OSHA
  • EPA
  • ACGIH
  • FDA

Correct Answer: ACGIH

Q7. Which statement best distinguishes TLVs from PELs?

  • TLVs are legally enforceable limits; PELs are advisory guidelines
  • TLVs and PELs are identical and issued by the same agency
  • TLVs are advisory guidelines published by ACGIH, while PELs are legally enforceable limits set by OSHA
  • TLVs apply only to biological monitoring while PELs apply to air concentrations

Correct Answer: TLVs are advisory guidelines published by ACGIH, while PELs are legally enforceable limits set by OSHA

Q8. Which formula correctly converts gas concentration from ppm to mg/m3 at 25°C and 1 atm?

  • mg/m3 = (ppm × 24.45) / molecular weight
  • mg/m3 = (ppm × molecular weight) / 24.45
  • mg/m3 = ppm × molecular weight × 24.45
  • mg/m3 = ppm / (molecular weight × 24.45)

Correct Answer: mg/m3 = (ppm × molecular weight) / 24.45

Q9. For evaluating combined exposure to two chemicals with similar toxic effects, which additivity relationship is used?

  • C1 + C2 ≤ TLV (sum of concentrations compared to one TLV)
  • C1/TLV1 + C2/TLV2 ≤ 1
  • C1 × TLV1 + C2 × TLV2 ≤ 1
  • max(C1/TLV1, C2/TLV2) ≤ 2

Correct Answer: C1/TLV1 + C2/TLV2 ≤ 1

Q10. What are Biological Exposure Indices (BEIs)?

  • Airborne concentration limits published by OSHA
  • Reference values for concentrations of chemicals or metabolites in biological specimens that indicate exposure
  • Environmental concentration limits for water contamination
  • Permissible limits for hazardous waste disposal

Correct Answer: Reference values for concentrations of chemicals or metabolites in biological specimens that indicate exposure

Q11. Which GHS pictogram specifically represents long-term health hazards such as carcinogenicity and respiratory sensitization?

  • Flame pictogram
  • Exclamation mark pictogram
  • Health hazard pictogram showing a silhouette of a person with a starburst on the chest
  • Corrosion pictogram

Correct Answer: Health hazard pictogram showing a silhouette of a person with a starburst on the chest

Q12. In a Safety Data Sheet (SDS), which section lists occupational exposure limits and engineering controls?

  • Section 3: Composition/Information on Ingredients
  • Section 8: Exposure Controls/Personal Protection
  • Section 2: Hazard Identification
  • Section 16: Other Information

Correct Answer: Section 8: Exposure Controls/Personal Protection

Q13. Which U.S. law primarily governs the manufacture and import of industrial chemicals and requires notification and reporting to EPA?

  • REACH
  • TSCA (Toxic Substances Control Act)
  • OSHA Act
  • Clean Air Act

Correct Answer: TSCA (Toxic Substances Control Act)

Q14. What is the primary objective of the EU REACH regulation?

  • To set legally enforceable TLVs across the EU
  • To register, evaluate, authorize and restrict chemical substances to protect human health and the environment
  • To provide occupational exposure limits for pharmaceuticals only
  • To harmonize pesticide registration across member states

Correct Answer: To register, evaluate, authorize and restrict chemical substances to protect human health and the environment

Q15. According to OSHA’s Hazard Communication Standard (HazCom 1910.1200), what must manufacturers provide to downstream users?

  • Only a label on the shipping container
  • Safety Data Sheets (SDS) and appropriate hazard labels for chemical shipments
  • Training certification for every employee handling the chemical
  • Monthly exposure monitoring results

Correct Answer: Safety Data Sheets (SDS) and appropriate hazard labels for chemical shipments

Q16. A worker is exposed to 25 ppm of solvent A (TLV = 100 ppm) and 60 ppm of solvent B (TLV = 200 ppm). Using the additivity rule, is the combined exposure within acceptable limits?

  • No, because the combined ratio exceeds 2.0
  • No, because each chemical individually exceeds its TLV
  • Yes, because 25/100 + 60/200 = 0.55 which is ≤ 1
  • Yes, because only the higher single concentration matters

Correct Answer: Yes, because 25/100 + 60/200 = 0.55 which is ≤ 1

Q17. Which exposure value is most appropriate for emergency response planning and respirator selection?

  • TLV-TWA
  • STEL
  • IDLH
  • BEI

Correct Answer: IDLH

Q18. Which U.S. institute recommends RELs (Recommended Exposure Limits) based on scientific review for occupational exposures?

  • OSHA
  • EPA
  • NIOSH
  • ACGIH

Correct Answer: NIOSH

Q19. Under the GHS system, which Hazard Statement corresponds to a chemical classified as a carcinogen?

  • H315: Causes skin irritation
  • H350: May cause cancer
  • H335: May cause respiratory irritation
  • H272: May intensify fire; oxidizer

Correct Answer: H350: May cause cancer

Q20. What is the correct order of the hierarchy of controls for mitigating chemical hazards from most to least effective?

  • PPE → Administrative Controls → Engineering Controls → Elimination
  • Engineering Controls → Substitution → Elimination → PPE
  • Elimination → Substitution → Engineering Controls → Administrative Controls → Personal Protective Equipment (PPE)
  • Administrative Controls → PPE → Engineering Controls → Substitution

Correct Answer: Elimination → Substitution → Engineering Controls → Administrative Controls → Personal Protective Equipment (PPE)

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