Hazard Communication and GHS

What HazCom Is and Where It Lives

The Hazard Communication Standard (HCS) – often called HazCom or the "Right-to-Know" standard – ensures that workers and supervisors know the identity and hazards of every chemical on site and how to protect themselves. The base standard is 29 CFR 1910.1200; construction adopts it through 29 CFR 1926.59, which simply points to the 1910 text. HazCom is perennially in OSHA's top-cited violations, so the STSC weights it heavily.

In 2012 OSHA aligned the HCS with the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS). This replaced the old Material Safety Data Sheet (MSDS) with the standardized Safety Data Sheet (SDS) and introduced uniform labels and pictograms.

The Four (Plus One) Pillars of a Written Program

A compliant employer hazcom program must contain:

1. A written hazard communication program describing how the site meets the standard.
2. A chemical inventory – a list of all hazardous chemicals on site.
3. Labels on every container.
4. Safety Data Sheets readily accessible to workers on every shift.
5. Worker training on the program, labels, SDS, and chemical hazards.

Training is required at initial assignment and whenever a new hazard is introduced. Workers must be able to locate and interpret an SDS quickly.

GHS Label Elements – Memorize Six

Every shipped container of a hazardous chemical must carry a GHS-compliant label with six required elements. This list is a guaranteed exam item:

Signal Words – Only Two

GHS uses exactly two signal words, and the distinction is tested directly:

• DANGER – used for the more severe hazard categories.
• WARNING – used for the less severe categories.

A label carries only one signal word – the one for the most severe hazard present. If a question lists "Caution," "Notice," or "Poison" as signal words, those are wrong – they are old MSDS-era terms, not GHS.

Pictograms – Nine Defined, Eight Enforced

GHS defines nine pictograms, each a black symbol inside a red-bordered diamond on a white background. OSHA enforces eight of them; the ninth, the Environment pictogram (a dead tree and fish), is the EPA's domain, not OSHA's. Know the eight OSHA cares about:

• Health Hazard (figure with a starburst chest) – carcinogen, respiratory sensitizer, reproductive toxicity.
• Flame – flammables, pyrophorics, self-heating.
• Exclamation Mark – irritant, skin sensitizer, narcotic effects.
• Gas Cylinder – gases under pressure.
• Corrosion – skin/eye burns, metal corrosive.
• Exploding Bomb – explosives, self-reactive, organic peroxides.
• Flame Over Circle – oxidizers.
• Skull and Crossbones – acute (severe) toxicity.

Do not confuse GHS pictograms with the old NFPA 704 diamond (the blue/red/yellow/white 0-4 rating). NFPA is for emergency responders, not worker right-to-know labeling – a common distractor.

The 16-Section Safety Data Sheet

The SDS follows a fixed 16-section order so any worker can find the same information in the same place on any chemical. You should know the early sections, which appear in scenario questions:

1. Identification
2. Hazard(s) Identification
3. Composition / Ingredients
4. First-Aid Measures
5. Fire-Fighting Measures
6. Accidental Release Measures
7. Handling and Storage
8. Exposure Controls / PPE

Sections 9–16 cover physical/chemical properties, stability/reactivity, toxicology, ecological, disposal, transport, regulatory, and other information. Sections 12–15 (ecological, disposal, transport, regulatory) are not OSHA-enforced because they fall under other agencies, but they must still appear.

HCS 2024 – the GHS Revision 7 Update

The STSC may reference the modernized rule. OSHA published the HCS 2024 final rule on May 20, 2024 (effective July 19, 2024), aligning the standard with GHS Revision 7. Phased compliance deadlines:

• Substance labels and SDS: update by January 19, 2026.
• Mixture labels and SDS: update by July 19, 2027.

During the transition, employers may comply with HCS 2012, HCS 2024, or both.

Common Traps and the Supervisor's Duty

• Confusing MSDS (old) with SDS (current 16-section format) – the SDS is correct.
• Listing "Caution" or "Poison" as a GHS signal word – only Danger and Warning exist.
• Mixing up GHS pictograms with the NFPA 704 fire diamond.
• Forgetting that secondary/workplace containers must also be labeled (at minimum the product identifier and hazard information) when a chemical is transferred from its original container and not used immediately.

The supervisor's core duty: ensure every container is labeled, every SDS is accessible on every shift, and every worker is trained to read both before handling the chemical.

Multi-Employer Sites and HazCom

Construction sites are almost always multi-employer, and HazCom has a specific rule for this. When a contractor brings a hazardous chemical onto a shared site, the host or controlling employer's program must address how SDSs are made available to other on-site employers, how labeling is handled in shared work areas, and how each employer informs the others of the hazards their workers may encounter and the protective measures needed. A subcontractor cannot assume the general contractor will warn its crew – the duty to communicate runs both ways.

Expect a scenario where two trades work in the same area and the question asks who must share SDS and hazard information; the answer is that each employer must, through the site program.

Workplace (Secondary) Container Labeling

A frequent field violation: a worker pours a solvent or fuel from its labeled drum into an unlabeled bucket or spray bottle. Secondary (workplace) containers must be labeled with at least the product identifier and the general hazard information (words, pictures, symbols, or a combination that conveys the hazards) unless the chemical is used immediately by the person who transferred it and the container is emptied at the end of the shift. Relabeling or leaving a transferred chemical for the next shift without a workplace label is a citable hazcom failure and a common exam trap.

Training Content and Timing

HazCom training is not a one-time orientation checkbox. Workers must be trained at initial assignment and whenever a new chemical hazard is introduced into their work area. Required content includes the operations where hazardous chemicals are present, the location and availability of the written program and SDSs, how to detect the presence or release of a chemical (monitoring, appearance, odor), the physical and health hazards, the protective measures (work practices, engineering controls, PPE, emergency procedures), and how to read labels and SDSs.

The supervisor verifies comprehension, not just attendance – a signed roster alone does not prove the worker can interpret a pictogram or find Section 8 of an SDS.