Chemical Safety

hazardous substances

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Hazardous substances in chemical safety: what they are and why they matter

Hazardous substances are at the center of most workplace chemical safety programs because they can harm people, property, or the environment if handled improperly. For many organizations, the biggest challenge isn’t knowing that chemicals can be dangerous—it’s consistently identifying hazards, maintaining accurate documentation, and ensuring employees can access the right information at the right time.

In the U.S., OSHA’s Hazard Communication Standard (HazCom), 29 CFR 1910.1200, sets the baseline requirements for chemical hazard classification, labeling, Safety Data Sheets (SDSs), and employee training. Understanding what qualifies as a hazardous substance (and how to manage it) is essential for compliance and for preventing injuries and exposures.

Hazardous substance definition (and how OSHA frames it)

People often search for a single “hazardous substance definition,” but in practice the meaning depends on the regulatory context. In everyday workplace safety discussions, hazardous substances generally refer to chemicals that present physical hazards (like flammability or explosivity) or health hazards (like toxicity, skin corrosion, or carcinogenicity).

Define hazardous substances under HazCom

If you want to define hazardous substances in a way that aligns with OSHA HazCom, focus on the term OSHA uses: “hazardous chemical.” Under 29 CFR 1910.1200, a hazardous chemical is any chemical classified as a health hazard or physical hazard. That includes many common products—solvents, acids, fuels, aerosols, cleaning agents, compressed gases, and more.

What that means operationally:

  • If a chemical is classified as hazardous, the employer must maintain an SDS for it (29 CFR 1910.1200(g))
  • Containers must be labeled with required hazard information (29 CFR 1910.1200(f))
  • Employees must be trained and have access to hazard information (29 CFR 1910.1200(h))

If a chemical is hazardous, it must be treated as a controlled safety risk—not just “another product on the shelf.”

Why there isn’t one universal definition

Different agencies use different terms for different purposes. For example, EPA programs may use “hazardous substance” in ways that don’t perfectly match OSHA HazCom. For workplace chemical safety, the most practical approach is to apply HazCom’s classification framework and manage chemicals as “hazardous” when they meet physical/health hazard criteria and require SDS communication.

“A hazardous substance is associated with its” hazards: what that really means

The keyword phrase “a hazardous substance is associated with its …” is often completed by words like toxicity, reactivity, exposure risk, or dose. The key idea is that a substance is not “hazardous” in a vacuum—it is associated with its:

  • Intrinsic hazards (e.g., corrosive, flammable, sensitizer)
  • Exposure routes (inhalation, skin contact, ingestion, injection)
  • Dose and concentration (higher exposure typically increases risk)
  • Form and conditions of use (dust vs. liquid; heated vs. room temperature)
  • Controls in place (ventilation, PPE, closed systems, procedures)

In other words, the hazard comes from the chemical’s properties, but the risk comes from how people may be exposed during real work.

Common categories of hazardous substances in the workplace

OSHA HazCom incorporates GHS-aligned categories of hazards. While you don’t need to memorize every classification, you should recognize the main buckets that frequently show up on SDSs.

Health hazards

Health hazards are associated with acute or long-term impacts on the body. Examples include:

  • Acute toxicity (harmful or fatal after short-term exposure)
  • Skin corrosion/irritation and serious eye damage/irritation
  • Respiratory or skin sensitization (allergic reactions)
  • Carcinogenicity, reproductive toxicity, and specific target organ toxicity (STOT)
  • Aspiration hazard (e.g., certain hydrocarbons)

Physical hazards

Physical hazards relate to chemical reactions, fire, or explosion potential. Examples include:

  • Flammable gases/liquids/solids
  • Oxidizers
  • Self-reactives and organic peroxides
  • Corrosive to metals
  • Gases under pressure
  • Explosives

Simple examples you may be overlooking

A “hazardous substance” isn’t always an exotic industrial chemical. Many workplaces routinely use:

  • Isopropyl alcohol (flammable)
  • Bleach and acids (corrosive; may generate toxic gases if mixed)
  • Spray adhesives and paints (flammable; inhalation hazards)
  • Compressed gas cylinders (pressure hazards)

How to identify hazardous substances: SDSs, labels, and inventory

Chemical safety programs break down when organizations can’t confidently answer: What chemicals do we have, where are they, and what are the hazards?

Use the SDS as your primary hazard reference

Under 29 CFR 1910.1200(g), SDSs must be readily accessible to employees when they are in their work area(s). SDSs provide standardized information, including:

  • Hazard identification
  • Composition/ingredients
  • First-aid measures
  • Fire-fighting measures
  • Handling and storage
  • Exposure controls/PPE

Verify container labels match hazards

HazCom requires labels on shipped containers and workplace containers, including hazard statements and pictograms where applicable (29 CFR 1910.1200(f)). Labeling is often where gaps show up—secondary containers, temporary bottles, and “unmarked” spray bottles are frequent compliance issues.

Maintain a complete chemical inventory

A current inventory supports training, SDS completeness, and risk control. It also helps you plan for storage compatibility, expiration dates, and emergency response.

This is where a platform like SwiftSDS can reduce administrative burden: you can centralize your SDS library in a secure cloud-based system, track chemical locations and quantities, and ensure employees have mobile access to the SDSs they need—supporting HazCom compliance and day-to-day safety.

For related guidance, see Safety Data Sheets.

OSHA compliance essentials for hazardous substances

A strong chemical safety program aligns with HazCom requirements and makes them operational.

Build (and maintain) a written HazCom program

OSHA requires employers to develop, implement, and maintain a written hazard communication program (29 CFR 1910.1200(e)). This program typically documents:

  • How SDSs are managed and made accessible
  • Labeling procedures (including secondary containers)
  • Training approach
  • How the chemical inventory is maintained

Train employees to understand hazards and protections

Training must cover hazardous chemical information and protective measures (29 CFR 1910.1200(h)), such as:

  • How to read labels and SDSs
  • Safe handling and storage practices
  • Required PPE and exposure controls
  • What to do in spills, leaks, or exposures

Keep SDS access practical—not theoretical

“Readily accessible” means employees can get the SDS information without barriers during their work shift. Cloud-based and mobile access can be a major advantage—especially for distributed operations, multiple shifts, or field work.

SwiftSDS supports this by providing any-device access to SDSs, helping employees and supervisors quickly locate critical hazard and first-aid information when seconds matter.

Best practices for managing hazardous substances safely

Beyond baseline compliance, these practices help reduce incidents:

  1. Standardize chemical receiving: verify labels, confirm SDS is present, and log the chemical into inventory.
  2. Control storage compatibility: segregate acids, bases, oxidizers, flammables, and reactives.
  3. Reduce chemical clutter: dispose of expired or unneeded chemicals to reduce risk.
  4. Use exposure controls first: ventilation and closed systems before relying solely on PPE.
  5. Audit secondary containers: ensure workplace labels are consistent and durable.
  6. Run periodic SDS and inventory reviews: confirm you have the latest SDS revisions and correct locations.

The goal is a living program: accurate inventory, current SDSs, clear labels, and trained employees.

Make hazardous substance management easier with SwiftSDS

Managing hazardous substances is ultimately an information and access problem: correct hazard classifications, correct SDSs, correct labels, and quick employee access—every time. SwiftSDS helps by centralizing your SDS library, supporting OSHA HazCom and GHS-aligned communication, tracking chemical inventory details (locations, quantities, expiration dates), and enabling mobile SDS access for workers.

Call to action: Ready to simplify hazardous substance documentation and strengthen OSHA compliance? Explore how SwiftSDS can streamline your SDS library, inventory tracking, and worker access—so your chemical safety program is accurate, audit-ready, and easier to run day to day.