CHMM Occupational Health And Safety 4 — Questions and Answers
Question 1: A chemical has a Threshold Limit Value-Ceiling (TLV-C) designation. What does this mean for worker exposure?
- Exposure must not exceed this concentration at any time, even instantaneously (Correct answer)
- The concentration is a 15-minute short-term exposure limit
- The time-weighted average must stay below this level over 8 hours
- Exposure above this level requires supplied-air respirators only
Correct answer: Exposure must not exceed this concentration at any time, even instantaneously
A TLV-C is an absolute ceiling concentration that must never be exceeded at any point during the workday, regardless of duration.
Question 2: Which OSHA standard requires employers to develop a written Hazardous Waste Operations and Emergency Response (HAZWOPER) plan for uncontrolled hazardous waste sites?
- 29 CFR 1910.120 (Correct answer)
- 29 CFR 1910.119
- 29 CFR 1910.1200
- 29 CFR 1926.65
Correct answer: 29 CFR 1910.120
29 CFR 1910.120 (HAZWOPER) requires a written safety and health program, medical surveillance, training, and emergency response plans for hazardous waste site workers.
Question 3: In toxicology, what term describes the dose-response relationship concept that 'the dose makes the poison'?
- Hormesis
- Paracelsus principle (Correct answer)
- Threshold effect
- Synergistic toxicity
Correct answer: Paracelsus principle
The Paracelsus principle — 'sola dosis facit venenum' (only the dose makes a poison) — is the foundational concept that all substances can be toxic at sufficient doses.
Question 4: Which personal protective equipment level provides the highest level of skin, respiratory, and eye protection under EPA guidelines?
- Level B
- Level C
- Level D
- Level A (Correct answer)
Correct answer: Level A
Level A PPE includes a fully encapsulating chemical-protective suit with SCBA, offering the maximum protection against vapors, gases, and skin absorption hazards.
Question 5: Under OSHA's respiratory protection standard (29 CFR 1910.134), before an employee is fit-tested for a tight-fitting respirator, what must be completed first?
- At least 8 hours of respirator training
- A medical evaluation by a physician or licensed health professional (Correct answer)
- Selection of the specific respirator model and cartridge type
- A qualitative fit test using BitrexTM solution
Correct answer: A medical evaluation by a physician or licensed health professional
OSHA requires medical evaluation before fit testing to ensure the employee is physically capable of wearing a respirator without adverse health effects.
Question 6: What does the term 'immediately dangerous to life or health' (IDLH) concentration represent?
- The concentration causing irreversible effects after 30 days of exposure
- The maximum concentration from which a worker could escape within 30 minutes without irreversible harm (Correct answer)
- The OSHA-enforced permissible exposure limit for acutely toxic substances
- The concentration causing a 50% fatality rate in animal studies
Correct answer: The maximum concentration from which a worker could escape within 30 minutes without irreversible harm
IDLH is defined by NIOSH as the maximum concentration from which a worker can escape within 30 minutes without escape-impairing symptoms or irreversible health effects.
Question 7: A company uses benzene as a solvent. Under OSHA 29 CFR 1910.1028, what is the action level for benzene that triggers medical surveillance?
- 0.1 ppm as an 8-hour TWA
- 0.5 ppm as an 8-hour TWA (Correct answer)
- 1 ppm as an 8-hour TWA
- 2.5 ppm as an 8-hour TWA
Correct answer: 0.5 ppm as an 8-hour TWA
OSHA's benzene standard sets an action level of 0.5 ppm (8-hr TWA); workers exposed at or above this trigger medical surveillance requirements.
CHMM Occupational Health And Safety 4
A chemical has a Threshold Limit Value-Ceiling (TLV-C) designation.
What does this mean for worker exposure?