Decoding Hazard Communication Labels for Safety

Why Labels Matter

When you need to know whether a chemical is hazardous, the label is your first source of information. OSHA’s Hazard Communication Standard requires that all labels follow a standardized format, giving you quick, reliable information about chemical risks. Even though labels might vary slightly between manufacturers, the core components are always consistent.

Chemical manufacturers, importers, and distributors are responsible for labeling each container leaving their facility. These labels must be legible, in English, and remain visible on the container. Employers, in turn, must ensure that the labels stay intact and are not removed or defaced once on-site. While English is mandatory, additional languages may be included to accommodate non-English-speaking workers.

Labeling in Practice

In certain situations, alternative systems like placards, process sheets, or batch tickets may be used if they effectively communicate the necessary hazard information and remain accessible in the work area throughout each shift. For example, transferring a chemical to a secondary container still requires labeling—unless the chemical is transferred and used immediately by the same employee, during the same shift.

Required Elements on Every Label

Every hazardous chemical label must include the following:

• Product Identifier – The name or number that links the label to the Safety Data Sheet (SDS).
• Signal Word – Indicates the severity of the hazard (e.g., “Danger” for serious, “Warning” for less severe).
• Hazard Statements – Standardized wording that describes the nature and degree of the hazard.
• Precautionary Statements – Instructions on safe handling, storage, response, and disposal.
• Pictograms – Visual symbols representing hazard types (e.g., flame, skull and crossbones).
• Supplier Identification – Name, address, and phone number of the manufacturer or importer.

For small containers (100 mL or less), OSHA allows reduced labeling—typically just the product identifier, pictograms, signal word, and a reference to the full label on the outer packaging—so long as the complete label appears on the outer package.

Interpreting a Sample Label

On a properly labeled container, you’ll find all six required elements. Here’s how they typically appear:

• Pictograms: Visual clues indicating the type of risk (e.g., flammability, health hazard).
• Signal Word: Prominently displayed. For example, "Danger" means this is a high-risk chemical.
• Hazard Statement: Provides detail. Example: "Highly flammable liquid and vapor. May cause liver and kidney damage."
• Precautionary Statements: Guide safe use. Example: "Keep container tightly closed. Store in a cool, well-ventilated place. Use non-sparking tools."
• First Aid Instructions: Critical actions to take in an emergency, such as “Remove contaminated clothing immediately” and “Rinse skin with water.”
• Product Identifier and Supplier Info: Ensures you know the exact substance and who to contact for more information.

NFPA and DOT Labels

In addition to OSHA labels, you might encounter NFPA or DOT labels on hazardous materials.

NFPA 704 Labels

These diamond-shaped signs are primarily for emergency response. They feature four color-coded quadrants. Blue, Red, and Yellow are rated from 0 (minimal) to 4 (severe) based on the level of hazard.

• 🔵 Blue – Health Hazard: Indicates the level of harm a substance can cause with short- or long-term exposure.
• 0 = No hazard
• 1 = Slight irritation
• 2 = Temporary incapacitation or possible residual injury
• 3 = Serious temporary or moderate permanent injury
• 4 = Severe, potentially fatal exposure with short contact
• 🔴 Red – Flammability Hazard: Measures how easily a substance ignites.
• 0 = Will not burn
• 4 = Ignites easily at room temperature
• 🟡 Yellow – Instability/Reactivity Hazard: Indicates how likely a substance is to explode or react violently.
• 0 = Stable
• 4 = May detonate or explode under normal conditions
• ⚪ White – Special Hazard Codes:
• OX = Oxidizer (e.g., ammonium nitrate)
• W (strikethrough) = Reacts dangerously with water (e.g., potassium)
• SA = Simple asphyxiant gas (e.g., nitrogen, helium)

NFPA labels are typically posted on buildings, tanks, or large fixed containers to help first responders quickly assess chemical risks in emergencies.

DOT Hazard Labels

The Department of Transportation (DOT) requires hazard labels on chemical shipments. These:

1. Use distinct background colors to denote hazard class (e.g., red for flammables, yellow for oxidizers).
2. Indicate transport restrictions and emergency protocols.
3. Must be placed on both bulk shipments (like tankers or railcars) and smaller non-bulk packages that contain hazardous materials.

For more info on DOT labeling, consult DOT Chart 17, a comprehensive guide with visuals and instructions for each hazard class.

Final Thoughts

Hazard labels are your first line of defense when handling chemicals. They deliver immediate, actionable insights and point you to deeper guidance found in the SDS. Know the label format, recognize the icons, and always ask questions if anything is unclear. Your safety depends on it. The Right to Understand starts with knowing how to read—and act on—hazard labels.