How to Conduct a Respiratory Hazard Assessment

Key Requirement: Employers must identify and evaluate respiratory hazards in the workplace before selecting respirators or implementing a respiratory protection program, per OSHA 29 CFR 1910.134(d)(1)(iii).

A respiratory hazard assessment is the critical first step in protecting workers from airborne contaminants. Without a thorough evaluation, employers cannot select appropriate respirators or implement effective controls. This guide walks you through the complete process of conducting a respiratory hazard assessment that meets OSHA requirements.

OSHA PPE Standard Requirements

OSHA's Respiratory Protection Standard (29 CFR 1910.134) requires employers to:

• Identify and evaluate respiratory hazards in the workplace
• Include reasonable estimates of employee exposures
• Identify the chemical state and physical form of contaminants
• Determine if oxygen-deficient atmospheres may exist
• Update assessments when workplace conditions change

The standard applies to all general industry workplaces where respiratory hazards are present or potentially present.

Step-by-Step Guide to Conducting a Respiratory Hazard Assessment

Step 1: Evaluate the Workplace

Begin with a comprehensive walkthrough of all work areas. Identify:

• Chemical products used (review Safety Data Sheets)
• Processes that generate dusts, fumes, mists, or vapors
• Confined spaces or poorly ventilated areas
• Tasks that disturb existing materials (grinding, sanding, welding)
• Potential for oxygen-deficient or oxygen-enriched atmospheres

Document every area where airborne contaminants may be present, even if exposures seem minimal.

Step 2: Document Hazards with a Job Hazard Analysis (JHA)

For each identified hazard, document:

• The specific contaminant(s) present
• Chemical state (gas, vapor, mist, fume, dust)
• Physical form and particle size
• Duration and frequency of exposure
• Number of workers potentially exposed
• Existing engineering controls in place

A Job Hazard Analysis breaks down each task into steps and identifies the respiratory hazards at each stage.

Step 3: Determine Exposure Level

Quantify worker exposure through:

• Air monitoring: Personal breathing zone samples provide the most accurate exposure data
• Area monitoring: Helps identify general contamination levels
• Historical data: Previous monitoring results and industry exposure data
• Modeling: Mathematical estimates based on process parameters

If monitoring is not feasible, use reasonable worst-case estimates that account for process variability.

Step 4: Compare to Permissible Exposure Limits (PELs)

Compare measured or estimated exposures to applicable limits:

Always compare to the most protective applicable limit. If exposures exceed PELs, engineering controls must be considered first, with respirators as supplemental protection.

Step 5: Select the Appropriate Respirator

Based on the hazard assessment, select respirators that provide adequate protection:

Step 6: Communicate and Train

After completing the assessment:

• Document all findings in writing
• Share results with affected employees
• Provide training on identified hazards
• Explain the basis for respirator selection
• Include assessment results in the written respiratory protection program

Types of Respiratory Hazards

Implementation Best Practices

• Review SDSs thoroughly — They provide hazard information, exposure limits, and recommended PPE
• Monitor regularly — Conditions change; reassess when processes, chemicals, or controls change
• Consider worst-case scenarios — Upset conditions, spills, and equipment failures can dramatically increase exposures
• Involve workers — Employees often have the best knowledge of actual task conditions
• Document everything — Written records demonstrate compliance and support future assessments
• Use hierarchy of controls — Elimination and engineering controls should be considered before respirators
• Account for multiple contaminants — When multiple chemicals are present, consider additive or synergistic effects

Frequently Asked Questions

How often must a respiratory hazard assessment be updated?

OSHA does not specify a fixed schedule, but assessments must be updated whenever workplace conditions change — including new chemicals, processes, equipment, or ventilation modifications. Best practice is to review annually.

Can I use qualitative assessments instead of air monitoring?

Yes, in some cases. OSHA allows "reasonable estimates" of exposure when monitoring is not feasible. However, air monitoring provides the most defensible data and is recommended whenever possible.

What if exposures are below the PEL?

If exposures are below the PEL and no other standard requires respirator use, respiratory protection may be voluntary. However, employers must still provide the information in Appendix D of the standard to voluntary users.

Who is qualified to conduct a respiratory hazard assessment?

OSHA does not specify credentials, but the assessor should have knowledge of industrial hygiene principles, air monitoring techniques, and the specific workplace processes being evaluated. Many employers use Certified Industrial Hygienists (CIHs).

What documentation is required?

The written respiratory protection program must include the assessment results, including the identity and concentration of hazards, the basis for respirator selection, and the conditions under which respirators must be worn.

Sources

• OSHA 29 CFR 1910.134 — Respiratory Protection Standard
• OSHA 29 CFR 1910.134(d)(1)(iii) — Hazard Evaluation Requirements
• NIOSH Respirator Selection Logic (2004)
• AIHA/ANSI Z88.6 — Respiratory Protection — Respirator Use
• ACGIH TLVs and BEIs Documentation
• OSHA Small Entity Compliance Guide for Respiratory Protection

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