3.2 Hazard Communication, SDS, and GHS

The OSHA Hazard Communication Standard (HCS), 29 CFR 1910.1200, is the federal right-to-know rule for hazardous chemicals. Manufacturers and importers must classify chemical hazards. Employers must pass that information to workers through labels, Safety Data Sheets (SDS), and training. OSHA aligned HCS with the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS) in 2012, and a 2024 OSHA update further aligns U.S. rules with later GHS revisions. The CMLA outline tests both the HCS workflow and GHS itself because assistants handle bleach, alcohols, and acid reagents around waived and point-of-care testing every shift.

Quick Answer: Read the GHS label—product identifier, Danger or Warning, pictograms, and hazard statements—before you open a bottle. Use SDS Section 2 for hazards, Section 4 for first aid, Section 7 for handling and storage, and Section 8 for PPE. A secondary container that sits on the bench needs a product identifier and hazard information. Do not confuse the NFPA 704 fire diamond (4 = most severe) with GHS categories (Category 1 = most severe).

What Hazard Communication Requires in the Laboratory

HCS applies whenever hazardous chemicals are used at work. The employer must keep an inventory, maintain an SDS for each product, make every SDS accessible on the shift (a binder or an electronic system is acceptable if there is no login barrier in an emergency), leave manufacturer GHS labels intact, label secondary workplace containers, and train employees before they work with the chemicals and again when a new hazard is introduced.

You are not expected to classify chemicals from first principles. You are expected to use the label and SDS instead of a coworker’s nickname for a reagent. "The blue stuff" is not a hazard communication system.

GHS Pictograms and Signal Words

GHS uses standardized pictograms—red diamond frames with black symbols on white—to flag hazard classes. OSHA requires the health-hazard, flame, exclamation-mark, gas-cylinder, corrosion, exploding-bomb, flame-over-circle (oxidizer), and skull-and-crossbones pictograms when those hazards are present. The environmental (dead fish and tree) pictogram is not mandatory under OSHA HCS, even though imported labels may still show it.

Signal words communicate severity. Danger marks more severe hazards. Warning marks less severe hazards. A label carries only one signal word—the more severe one if both would otherwise apply. Caution is not a GHS signal word. If an exam option treats Caution as equivalent to Danger, it is a distractor.

Hazard statements (for example, "Causes severe skin burns and eye damage") and precautionary statements (prevention, response, storage, disposal) complete the label. The product identifier on the bottle must match the identifier on the SDS so you can find the right sheet during a splash.

The 16-Section SDS — Pages Assistants Actually Open

GHS standardized the SDS into 16 numbered sections. OSHA currently enforces the content of Sections 1–11 most directly; Sections 12–15 still appear on almost every sheet even though other agencies govern ecology, disposal, transport, and some regulatory listings. For waived-testing and bench work, four sections do most of the job:

Be able to name the others: Section 1 identification (product and supplier), Section 3 composition, Section 5 fire-fighting, Section 6 accidental release (chemical spill), Section 9 physical and chemical properties, Section 10 stability and reactivity, Section 11 toxicology, and Section 16 other information (including the revision date). If bleach hits the eye, start at Section 4, not Section 16. Section 2 tells you the hazard class; it does not replace the first-aid steps. Section 8 tells you which gloves to put on before the next pour.

Chemical Hygiene Plan Versus SDS

Do not treat the chemical hygiene plan (CHP) and the SDS as the same document. The SDS is the manufacturer or importer document for one chemical or mixture. The CHP is the laboratory’s written program—typically required under the OSHA Laboratory Standard, 29 CFR 1910.1450—that describes how this laboratory will protect workers: standard operating procedures, PPE policy, fume-hood use, waste handling, training, and the designated chemical hygiene officer.

If the SDS says a reagent is corrosive and the CHP says acids are used only in a designated area with a functioning eyewash, you follow both. The SDS does not replace the CHP, and a CHP binder does not replace the SDS for a new lot of bleach.

Secondary Container Labeling

When you pour 10% bleach into a spray bottle, or aliquot alcohol into a squeeze bottle that will sit at the phlebotomy station, that bottle is a secondary (workplace) container. HCS requires it to carry the product identifier plus words, pictures, symbols, or a combination that communicate the hazards. GHS pictograms and a signal word are the cleanest way to do that. Tape that says only "bleach" with no hazard cue is not enough if someone else could pick the bottle up.

The narrow exception is a portable container intended only for immediate use by the employee who transferred the chemical. Immediate use does not mean "I will get back to it after lunch," and it does not mean "the original bottle is still in the room." If the container remains on the bench for the shift, label it.

Fire Diamond Versus GHS — The Numbering Trap

The NFPA 704 fire diamond is a facility and emergency-response placard, not a GHS label. Blue is health, red is flammability, yellow is instability, and white is special hazards (for example OX for oxidizer, W with a bar for water-reactive). Numbers run 0 (minimal) to 4 (severe).

GHS hazard categories generally run the opposite direction: Category 1 is the most severe. A GHS Flammable Liquid Category 1 is more dangerous than Category 4. Never translate an NFPA 4 into a GHS 4. Both systems may appear in the same laboratory—NFPA diamonds on a door or cabinet, GHS on the bottle and SDS. Use each system on its own terms.

Reagents Used Around Waived Testing

Sodium hypochlorite (bleach) used to disinfect blood spills is corrosive and may also be classified as an oxidizer. Mixing bleach with acids or ammonia can release chlorine or chloramine gas—that incompatibility is why Section 7 exists. Prepare dilutions fresh when the SOP requires it; old dilute bleach loses available chlorine and then fails as a disinfectant and remains a chemical hazard.

Ethanol and isopropanol used as antiseptics and in some waived-test wipes are flammable liquids. Keep ignition sources away, recap bottles, and store bulk stock per the CHP (often a flammable cabinet). Expect a GHS flame pictogram plus Danger or Warning depending on flash point and concentration. An open alcohol bottle next to a bunsen burner or a heat block is a HazCom failure, not a BBP failure.

Acid reagents around some waived or point-of-care chemistry and occult-blood systems carry the corrosion pictogram. Splash risk makes the eyewash and Section 4 first-aid steps part of ordinary use. Neutralize and absorb chemical spills per SDS Section 6 and the CHP. Do not treat an acid spill as if it were a blood spill, and do not treat a blood spill as if the only issue were the acid in the cleaner. When both hazards are present, apply both standards.