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105 Hazard Communication: Basic
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105 Hazard Communication: Basic

Forms of Hazardous Chemicals

The chemicals that apply to the rule are not limited to those in liquid, gas, or particulate form. According to the HCS, hazardous chemicals can exist in various forms:

Image showing worker spray painting a vehicle
Hazardous mists produce vapors when spray painting.

Dusts: Finely divided particles. Example - wood dust.

Fumes: Smaller particles usually formed when solid metal is heated and vaporized, and then condensed as tiny particles.

Fibers: Similar to dusts but are of an elongated shape. Examples - asbestos and fiberglass.

Mists: Liquid droplets that have been sprayed into the atmosphere.

Vapors: Gases formed when liquid evaporates.

Gases: Substances that exist airborne at room temperature. A vapor is the gaseous phase of a substance usually existing as a liquid or solid at room temperature.

Solids: Examples include metal, treated wood, plastic.

Liquids: The most common form in the workplace.

Real-Life Accidents

At 2:45 p.m. on October 1, 2021, Employee #1 and Employee #2 who worked in production in an electroplating facility were draining a hydrochloric acid tank to replace the contents. The hose the employees were using had been previously used to move chlorine and had not been washed out afterward. When the employees began to use the hose to move the hydrochloric acid the acid and the chlorine reacted releasing chlorine gas. The employees were exposed resulting in chemical burns. Employee #1 was hospitalized for treatment due to inhaling chlorine. Employee #2 received medical treatment but did not require hospitalization.
At 1:43 p.m. on August 11, 2023, an employee was observing a production line when he went to the welding box and opened the door and a combustible dust explosion occurred and a resulting fire. The employee died from his injuries.

Knowledge Check Choose the best answer for the question.

1-4. What does OSHA define as small particles, usually formed when solid metal is heated and vaporized and then condenses as tiny particles?

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