STSC Health Hazards and Hygiene 4 — Questions and Answers
Question 1: A construction worker develops flu-like symptoms, muscle aches, and high fever after working near a cooling tower. Which occupational disease is most likely?
- Heat exhaustion
- Legionnaires' disease (Correct answer)
- Silicosis
- Metal fume fever
Correct answer: Legionnaires' disease
Legionnaires' disease is caused by Legionella bacteria that thrive in water systems like cooling towers and can be inhaled as aerosols.
Question 2: What is the primary route of entry for lead dust on a construction site into the human body?
- Skin absorption
- Eye contact
- Ingestion via contaminated hands (Correct answer)
- Direct injection
Correct answer: Ingestion via contaminated hands
Lead dust on construction sites is most commonly ingested when workers eat, drink, or smoke without washing contaminated hands first.
Question 3: Which type of respirator provides the highest level of respiratory protection for IDLH (Immediately Dangerous to Life or Health) atmospheres?
- Half-face air-purifying respirator
- Full-face air-purifying respirator
- Self-contained breathing apparatus (SCBA) (Correct answer)
- Filtering facepiece (N95)
Correct answer: Self-contained breathing apparatus (SCBA)
SCBA provides the highest level of protection by supplying clean breathing air independent of the surrounding atmosphere.
Question 4: What is the OSHA permissible exposure limit (PEL) for silica dust (respirable crystalline silica) as an 8-hour TWA?
- 0.05 mg/m³ (Correct answer)
- 0.5 mg/m³
- 1.0 mg/m³
- 5.0 mg/m³
Correct answer: 0.05 mg/m³
OSHA's PEL for respirable crystalline silica is 50 micrograms per cubic meter (0.05 mg/m³) as an 8-hour TWA.
Question 5: A supervisor notices workers developing dermatitis after handling wet cement. What is the primary cause?
- Allergic reaction to sand aggregates
- Hexavalent chromium and alkaline pH of cement (Correct answer)
- Dehydration of skin from dry powder
- Synthetic polymer additives
Correct answer: Hexavalent chromium and alkaline pH of cement
Wet cement causes skin damage due to its high alkalinity and the presence of hexavalent chromium, a known skin sensitizer and carcinogen.
Question 6: Which engineering control is most effective at reducing worker exposure to wood dust during cutting operations?
- Administrative rotation of workers
- Mandatory PPE for all workers
- Local exhaust ventilation (LEV) at the source (Correct answer)
- General dilution ventilation of the entire workspace
Correct answer: Local exhaust ventilation (LEV) at the source
Local exhaust ventilation captures dust at the point of generation before it becomes airborne and spreads, making it more effective than dilution ventilation.
Question 7: What medical condition can result from repeated hand-arm vibration exposure from tools like jackhammers over several years?
- Carpal tunnel syndrome only
- Hand-arm vibration syndrome (HAVS), including vibration white finger (Correct answer)
- Raynaud's disease caused by cold alone
- Epicondylitis (tennis elbow)
Correct answer: Hand-arm vibration syndrome (HAVS), including vibration white finger
HAVS is a chronic occupational disease affecting blood vessels, nerves, and muscles of hands caused by prolonged use of vibrating tools.
STSC Health Hazards and Hygiene 4
A construction worker develops flu-like symptoms, muscle aches, and high fever after working near a cooling tower.
Which occupational disease is most likely?