Laboratory Safety, Quality Assurance, and Chemical Hygiene
Scope
The exam tests the regulatory and practical framework of safe laboratory work - the Chemical Hygiene Plan, hazard communication, exposure limits, incompatible chemical storage, waste handling, spill response - together with the QA practices that make data traceable and reliable.
Core rules
- OSHA Laboratory Standard 29 CFR 1910.1450 requires a written Chemical Hygiene Plan, a designated Chemical Hygiene Officer, worker training, and exposure monitoring when hazards warrant it.
- GHS-aligned Safety Data Sheets have 16 sections: hazards first, then composition, first aid, firefighting, handling, exposure controls, and disposal.
- PEL and TLV are occupational exposure limits, usually 8-hour time-weighted averages; they are not thresholds of safety.
- Engineering controls come first (fume hood, local exhaust), then administrative controls and PPE.
- Store oxidizers away from organics, acids away from bases, and water-reactive metals away from aqueous waste.
- QA: documented SOPs, calibration, method blanks, duplicates, spikes, reference materials, and control charts.
Worked example
You must dilute concentrated sulfuric acid. Add the acid slowly to water with stirring and cooling, never water to acid. Dilution is highly exothermic; adding water on top of concentrated acid can boil the surface layer and eject acid. Work in a fume hood with splash goggles, face shield, acid-resistant gloves, and apron, and have a spill kit and eyewash access ready. Record the lot, volumes, and analyst in the notebook so the preparation is traceable.
Traps
- Pouring water into concentrated acid - a classic, serious error.
- Mixing incompatible waste streams, such as oxidizers with organics or acids with cyanides.
- Treating absence of odor as evidence of safe air; many toxics are odorless.
- Using a fume hood for biohazards or as storage space, which disrupts airflow and containment.