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OSHA Respiratory Protection Standard (29CFR 1910.134)

Respiratory Protection Adviser


Respiratory Hazards Assessment

Paragraph 1910.134(d)(1)(iii) of the respiratory standard, requires all employers whose employees are required to use respirators, to conduct a hazard evaluation for each operation, process, or work area where airborne contaminants may be present in routine operations, or during an emergency to:
  • Identify and develop a list of hazardous substances used at the site, for each operation or work process, to include the nature of the hazard, e.g. toxicity, chemical and physical properties.
  • Review work processes and operations and determine where potential exposures of identified hazardous substances may occur and make an inventory of those operations. 
  • Quantify extent of potential hazardous exposure (hazardous agent concentrations) and times of exposure (a DEHS Industrial Hygienist will provide monitoring when needed).
Exposure Assessment is Required When:
  • Employees are exposed to a respiratory hazard, or are required to wear respirators.
  • Substances with an OSHA specific standard(such as lead, methylene chloride, asbestos)are used.
  • Employees report symptoms of irritation, odors or complain of respiratory health effects.
  • The workplace contains visible emissions (e.g., fumes, dust, aerosols).
The employer must determine or provide a "reasonable estimate" of employee exposures anticipated to occur as a result of working with those hazards, including those likely to be encountered in reasonably foreseeable emergency situations

Types of Respiratory Hazards or Hazardous Agents

Workplace respiratory hazards may be present in the following forms:
  • Dusts and fibers - solid particles that are formed or generated from solid materials through mechanical processes such as crushing, grinding, drilling, abrading or blasting.  Examples of toxic dusts and fibers include lead, silica, and asbestos.

  • Fumes - solid particles that are formed when a metal or other solid vaporizes and the molecules condense (or solidify) in cool air.  Examples are metal fumes from smelting or welding.  Fumes also may be formed from processes such as plastic injection, or extrusion molding.

  • Mists - tiny droplets of liquid suspended in the air.  Examples are oil mist produced from lubricants used in metal cutting operations, acid mists from electroplating, and paint spray mist from spraying operations.

  • Gases - materials that exist as individual molecules in the air at room temperature.  Examples are welding gases, such as acetylene and nitrogen, and carbon monoxide produced from internal combustion engines.

  • Vapors - the gaseous form of substances that are normally in the solid or liquid state at room temperature and pressure. They are formed by evaporation. Most solvents/chemicals produce vapors.  Examples include benzene, methylene chloride, toluene, Nitric and hydrochloric  Acids, etc.

  • Biological hazards - include bacteria, viruses, fungi, and other living organisms that can cause acute and chronic infections if breathed in.  Examples include Legionnaire’s Disease, flour, and animal products and allergens (dander, excreta, saliva).

Types of Required Exposure Monitoring

While the standard allow the employers to use different approaches to estimate worker exposures to respiratory hazards.  To accurately quantify employee exposure in the workplace and to determine how much and what type of respiratory protection is required in any given circumstance. The University of Minnesota will use following approach:
  • Risk Assessmentand Job or Task Hazard Analysis to collect information on hazardous chemicals used and hazardous operations or processes. (see Risk Assessment for Job Hazard Analysis Training)
  • Personal Sampling/ Personal Exposure Monitoring to obtain workers accurate exposure information (DEHS Industrial Hygienist) for all substances regulated under the Air Contaminants standard (29 CFR 1910.1000), or by specific monitoring requirements as outlined in the OSHA substance-specific standards.

The University of Minnesota is an equal opportunity educator and employer.