What Are the Five General Hazard Categories?
OSHA recognizes five broad categories of workplace hazards that employers must identify, evaluate, and control. Understanding these categories is the foundation of every effective safety program and is essential for creating compliant evacuation maps that account for hazardous zones. The five categories are: Physical Hazards, Chemical Hazards, Biological Hazards, Ergonomic Hazards, and Psychosocial Hazards. Each category requires specific controls under OSHA's General Duty Clause (Section 5(a)(1)) and various specific standards.
1. Physical Hazards
Physical hazards are the most common workplace hazard category. They include: unguarded machinery and moving parts (29 CFR 1910.212), electrical hazards (29 CFR 1910 Subpart S), slips, trips, and falls (29 CFR 1910 Subpart D), noise exposure above 85 dB (29 CFR 1910.95), extreme temperatures, radiation, and vibration. Physical hazards are responsible for the majority of OSHA's 'Fatal Four' construction deaths: falls (36.4%), struck-by (9.8%), electrocutions (7.3%), and caught-in/between (4.4%). On evacuation maps, physical hazard zones should be clearly marked to ensure evacuation routes avoid these areas.
2. Chemical Hazards
Chemical hazards involve exposure to harmful substances in any form — liquids, gases, vapors, dusts, or fumes. OSHA regulates these through the Hazard Communication Standard (29 CFR 1910.1200), which requires Safety Data Sheets (SDS), proper labeling, and employee training. Common examples include cleaning solvents, welding fumes, asbestos, lead, and combustible dust. Chemical storage areas must be clearly marked on evacuation maps, and evacuation routes must be designed to move people away from chemical hazard zones.
3. Biological Hazards
Biological hazards (biohazards) include exposure to bacteria, viruses, fungi, parasites, and other living organisms that can cause illness. Industries most affected include healthcare (Bloodborne Pathogens Standard 29 CFR 1910.1030), agriculture, food processing, and laboratory work. Biological hazard areas — such as labs, patient isolation rooms, or waste processing areas — should be marked on evacuation maps with the universal biohazard symbol to alert evacuees and first responders.
4. Ergonomic Hazards
Ergonomic hazards result from workplace conditions that cause musculoskeletal disorders (MSDs). They include repetitive motions, awkward postures, forceful exertions, heavy lifting, and prolonged static positions. While OSHA has no specific ergonomics standard, employers are cited under the General Duty Clause. MSDs account for nearly 30% of all worker's compensation claims. Ergonomic hazards should be factored into evacuation planning — workstations that restrict movement may impede rapid egress during emergencies.
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Create Your Free MapHazard Identification Checklist
- Walk through every area of the workplace to identify physical hazards
- Review Safety Data Sheets for all chemicals on-site
- Assess biological exposure risks for each job role
- Evaluate workstation ergonomics and repetitive task exposure
- Document psychosocial risks including violence potential
- Map all identified hazards on your floor plan
- Mark hazard zones on evacuation maps with proper symbols
- Train employees on hazards specific to their work area
- Review and update hazard assessments at least annually
- Integrate hazard locations with emergency evacuation routes
Why Hazard Mapping Matters
Nonfatal workplace injuries reported to BLS in 2023
Musculoskeletal disorders as share of workers comp claims
Average cost per OSHA recordable workplace injury
Facilities with mapped hazards see 4x fewer incidents
Expert Hazard Assessment Tip
The most effective hazard assessments combine all five categories into one walkthrough. I use a simple color-coded system: red dots for physical hazards, orange for chemical, green for biological, blue for ergonomic, and purple for psychosocial. This visual approach makes it easy to transfer hazard locations onto your evacuation map. Remember — OSHA inspectors increasingly check whether your emergency plans account for facility-specific hazards, not just generic exit routes.