HSE Occupational Health and Hygiene Questions and Answers — Questions and Answers
Question 1: An industrial hygienist measures a worker's exposure to a solvent during a specific 15-minute task. To what type of Occupational Exposure Limit (OEL) should this short-term measurement be compared to determine if an immediate hazard exists?
- Threshold Limit Value - Time-Weighted Average (TLV-TWA)
- Permissible Exposure Limit (PEL)
- Short-Term Exposure Limit (STEL) (Correct answer)
- Immediately Dangerous to Life or Health (IDLH)
Correct answer: Short-Term Exposure Limit (STEL)
The Short-Term Exposure Limit (STEL) is specifically defined as a 15-minute time-weighted average exposure that should not be exceeded at any time during a workday. It is designed to protect workers from acute effects of exposure to chemicals. TLV-TWA and PEL are typically averaged over an 8-hour shift, while IDLH represents a concentration from which a worker could escape without irreversible health effects in the event of a respirator failure.
Question 2: A manufacturing facility has identified that several employees are consistently exposed to noise levels at an 8-hour time-weighted average (TWA) of 87 dBA. According to OSHA's Hearing Conservation Program requirements, which action is mandatory for these employees?
- Mandatory use of dual hearing protection (earplugs and earmuffs).
- Implementation of engineering controls to reduce noise below 85 dBA.
- Providing annual audiometric testing at no cost. (Correct answer)
- Restricting employee exposure time to less than 4 hours per shift.
Correct answer: Providing annual audiometric testing at no cost.
OSHA's action level for noise is an 8-hour TWA of 85 dBA. Once exposures meet or exceed this level, the employer must implement a hearing conservation program. A key component of this program is providing baseline and annual audiometric testing at no cost to all employees exposed at or above the action level to monitor for hearing loss. Mandatory hearing protection use is required at the Permissible Exposure Limit (PEL) of 90 dBA.
Question 3: An assembly line task requires workers to use a hand tool that forces their wrist into an awkward, bent posture. Which of the following represents the most effective ergonomic control for this hazard?
- Redesigning the tool with an angled handle to allow for a neutral wrist posture. (Correct answer)
- Training workers to perform wrist stretches every hour.
- Providing workers with wrist braces to wear during the task.
- Implementing a job rotation schedule to limit each worker's time on the task.
Correct answer: Redesigning the tool with an angled handle to allow for a neutral wrist posture.
According to the hierarchy of controls, engineering controls that physically change the workplace are the most effective. Redesigning the tool to eliminate the hazardous posture is an engineering control. Training and job rotation are less effective administrative controls, and providing wrist braces is a form of personal protective equipment, which is the least effective control measure.
Question 4: A healthcare professional must enter the room of a patient with a confirmed airborne infectious disease, such as tuberculosis. What is the minimum level of respiratory protection required to prevent inhalation of infectious aerosols?
- A standard surgical mask.
- A full-face shield.
- Safety goggles and a cloth face covering.
- A NIOSH-certified N95 respirator. (Correct answer)
Correct answer: A NIOSH-certified N95 respirator.
For diseases transmitted by airborne droplet nuclei, such as tuberculosis, a standard surgical mask is not sufficient as it does not seal to the face. The minimum requirement is a NIOSH-certified N95 respirator, which is designed to form a seal and filter at least 95% of airborne particles when properly fit-tested and worn.
Question 5: A worker is cleaning equipment with a volatile solvent in a confined space. This exposure is most likely to cause rapid, systemic toxic effects through which primary route of entry?
- Dermal absorption
- Inhalation (Correct answer)
- Ingestion
- Injection
Correct answer: Inhalation
Inhalation is typically the most common and rapid route of entry for airborne contaminants like solvent vapors in a workplace setting. The lungs provide a large surface area and a direct path to the bloodstream, allowing for quick absorption and distribution of the chemical throughout the body, leading to systemic effects. While absorption can occur, it's generally a slower process.
Question 6: Under OSHA's Hazard Communication Standard (HCS), which of the following information is required in Section 8 of a Safety Data Sheet (SDS) but is NOT required on the shipped container's label?
- Specific Occupational Exposure Limits (e.g., PELs, TLVs). (Correct answer)
- The Signal Word (e.g., 'Danger' or 'Warning').
- A Pictogram representing the primary hazard.
- A Hazard Statement (e.g., 'Causes skin irritation').
Correct answer: Specific Occupational Exposure Limits (e.g., PELs, TLVs).
The shipped container label is a summary of the most critical hazard information and must include the signal word, pictograms, and hazard statements. The Safety Data Sheet (SDS) is a more comprehensive document. Specifically, Section 8 of the SDS, 'Exposure Controls/Personal Protection,' must contain detailed information such as OSHA Permissible Exposure Limits (PELs) and ACGIH Threshold Limit Values (TLVs), which are not required on the label.
HSE Occupational Health and Hygiene Questions and Answers
An industrial hygienist measures a worker's exposure to a solvent during a specific 15-minute task.
To what type of Occupational Exposure Limit (OEL) should this short-term measurement be compared to determine if an immediate hazard exists?