What is the Definition of Hazardous Chemicals?

Under §1910.1200(c), OSHA defines a hazardous chemical as "any chemical which is classified as a physical hazard or a health hazard, a simple asphyxiant, combustible dust, pyrophoric gas, or hazard not otherwise classified."

If we asked you to give an example of a chemical hazard, you'd probably think of a few from public awareness campaigns – asbestos, lead, arsenic, or bleach. You might not know how to safely handle those substances, but you know that they're dangerous.

Then there are everyday items that you know require specific caution. For example, you know that gasoline should be kept away from an open flame and that glue or paint fumes can make you sick.

Unfortunately, there are also dangerous substances that you may have never heard of and chemical hazards you didn't know to worry about.

Thankfully, OSHA and other safety organizations have identified those for you, and they're planning ahead for new chemicals and unknown threats. That's why OSHA organizes chemical hazards into categories, rather than relying on a specific, comprehensive hazardous chemicals list.

What are Chemical Hazards?

OSHA's official definition of a hazardous chemical above specifies six broad categories of chemical hazard, but each of those categories have their own specific definitions.

First, OSHA mentions physical and health hazards. They define a health hazard as a chemical that causes:

• Acute toxicity (any route of exposure)
• Skin corrosion or irritation
• Serious eye damage or eye irritation
• Respiratory or skin sensitization
• Germ cell mutagenicity
• Carcinogenicity
• Reproductive toxicity
• Specific target organ toxicity (single or repeated exposure)
• An aspiration hazard

They define a physical hazard as a chemical that one of the following:

• Explosive
• Flammable (gases, aerosols, liquids, or solids)
• An oxidizer (liquid, solid, or gas)
• Self-reactive
• Pyrophoric (liquid or solid)
• Self-heating
• An organic peroxide
• Corrosive to metal
• Gas under pressure
• Emits flammable gas in contact with water

Then they throw in a few more hazards. A simple asphyxiant is "a substance or mixture that displaces oxygen in the ambient atmosphere and can thus cause oxygen deprivation in those who are exposed, leading to unconsciousness and death."

A pyrophoric gas "will ignite spontaneously in air at a temperature of 130°F (54.4°C) or below."

Combustible dust is defined as "a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations."

Finally, OSHA likes to plan for the unknown, so they created a catchall called Hazard Not Otherwise Classified (HNOC) for any "adverse physical or health effect identified through evaluation of scientific evidence" that doesn't meet the specific qualifying criteria in Appendix A (for health hazards) or Appendix B (for physical hazards) of §1910.1200.

The hazards presented by an HNOC need to be addressed on the Safety Data Sheets and communicated to employees just like any other chemical hazard, although Globally Harmonized System (GHS) labeling requirements don't apply.

Rules for Safe Handling of Chemicals in the Workplace

As we said, there are some general rules and best practices for avoiding chemical exposure or injury.

Know Your Chemicals

The guidance for safely handling a carcinogen that absorbs through the skin is very different from safely handling a gas that's under pressure.

That's why the first rule for avoiding chemical exposure or injury in the workplace is to pay attention to the GHS labels and follow all protocols in place. Only use hazardous materials for their intended purpose and always follow the best practices.

Reread labels for chemicals you don't use regularly to refresh your memory and avoid mistakes. Repeat training regularly to keep the information fresh. Everyone who works with or around a hazardous chemical should know the basic do's and don't's for dealing with a spill, leak, or exposure to that substance.

If someone demonstrates a lack of competency in safety protocol, they should be removed from related duties until they repeat the training and prove their proficiency.

Know Your Workplace

If something goes wrong, a fast response can save limbs or lives. That's why you need to know where emergency resources are located in any work area where you spend time.

You should know where the nearest Safety Data Sheets (SDSs) are stored so you can quickly access complete safety information in case of an incident.

You also need to know where the eyewash, emergency shower, and fire suppression systems are and how to activate them. If you're assigned to a new work area, make sure you note the location of emergency stations before you start working with or around chemical hazards.

Make sure you understand emergency procedures for your workplace. That includes emergency reporting protocol, evacuation procedures, and how to deal with a fire – including all fire types you may encounter.  You also need to be familiar with how to deal with medical emergencies, particularly those involving workplace chemicals.

Practice Good Hygiene

Regardless of the type of chemicals in your workplace, it's best practice to avoid eating or drinking while you handle hazardous chemicals. Even if the dangerous substance doesn't pose an absorption or ingestion threat, it can be distracting and lead to a life-threatening mistake.

Make it a habit to thoroughly wash your hands after handling hazardous chemicals, as well as before you eat or drink.

Keep your work area clean. Wipe down work surfaces frequently to minimize your contamination or exposure risk and keep the floor dry and free of clutter. Slipping, tripping, or falling is bad enough, but when you add dangerous substances, it can become deadly.

Make sure lids or valves on hazardous chemical containers are properly sealed when not in use. Store containers securely so they're not easily bumped, tipped, or knocked over.

Hazardous chemicals should be stored in appropriate containers. That means spill-proof or vapor-tight and composed of a material that won't be compromised by that substance.

Storage conditions also matter. Generally speaking, hazardous chemicals need to be kept in cool, dry, ventilated areas. Separate incompatible substances to minimize the chance of mixup or contact. Pest control is also important – you want to avoid contamination or container damage.

Use Proper PPE

Always use personal protective equipment (PPE) when handling hazardous chemicals, and not just any PPE – make sure it's effective against the chemical hazard you're dealing with.

Do you know what type of gloves protect your hands from hazardous chemicals? Typically some type of rubber is necessary, but sometimes polyvinyl or -ethylene works. No glove material protects against all substances, so you need to use the kind that's appropriate for the chemicals in your workplace.

That's equally true of goggles, respirators, and other categories of PPE. What's protective in one situation could be useless in another.

The fit and condition of PPE are also important. Respirators, for example, should be fit-tested annually to make sure it creates a proper seal. Poorly-fitting gloves, coveralls, and other PPE can also pose a risk.

Inspect all PPE carefully before each use. If it's worn or damaged, discard and replace it.

Fix or Report Potential Hazards

Everyone in the workplace is responsible for ensuring that dangerous substances are managed properly. If you see a potential hazard or a violation of safety regulations and best practices, you should address it immediately. Correct it if you know how, or report it if you don't.

Report missing or inaccurate labels and SDSs, damaged containers, and storage hazards. Report damaged, ill-fitting, or inadequate PPE.  Tell someone up the chain if chemicals are being mishandled or misused, or if you suspect that your training is out-of-date or inadequate.

If your concerns are ignored by your employer, you can report possible safety violations to OSHA anonymously. The agency also offers protection if your employer retaliates.

Learn More About Safe Handling of Chemicals in the Workplace

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