Hazard communication is a set of practices and legal requirements designed to make sure workers know about the chemical hazards in their workplace. In the United States, it’s governed by OSHA’s Hazard Communication Standard (HCS), found in federal regulation 29 CFR 1910.1200. The standard requires chemical manufacturers to classify hazards, put warning information on labels, provide detailed safety data sheets, and requires employers to train their workers on all of it. It’s consistently one of the most cited OSHA standards during workplace inspections, ranking second overall in fiscal year 2025.
How the Standard Works
The Hazard Communication Standard creates a chain of responsibility that starts with chemical manufacturers and flows downstream to employers and workers. Manufacturers and importers must evaluate every chemical they produce or bring into the country, classify its hazards, and then communicate those hazards through standardized labels and safety data sheets (SDS). Distributors must pass that information along without alteration.
Employers who use hazardous chemicals don’t have to do the classification themselves, but they carry their own set of obligations. They must maintain a written hazard communication program, keep safety data sheets accessible, make sure containers are properly labeled, and train every employee who might be exposed. The goal is straightforward: no worker should encounter a chemical without understanding what it can do and how to protect themselves.
The Written Program
Every employer who uses hazardous chemicals must prepare and implement a written hazard communication program. This document serves as the blueprint for how the workplace handles chemical safety, and it needs to cover three core areas: labeling, safety data sheets, and employee training.
The written program also requires a list of every hazardous chemical known to be present in the workplace. Each chemical is identified using the same product identifier that appears on its label and SDS, which makes it easier to track whether you have the right safety documents on file. This list functions as a master inventory. If an inspector walks in, the written program and chemical list are typically the first things they want to see.
What Goes on a Label
Chemical container labels are the first line of defense. Every container of a hazardous chemical shipped from a manufacturer or distributor must carry six elements:
- Product identifier: the name used to track the chemical across labels, SDS documents, and inventory lists
- Signal word: either “Danger” (for more severe hazards) or “Warning” (for less severe ones)
- Hazard statements: standardized phrases describing the nature of the hazard, such as “causes serious eye damage”
- Precautionary statements: recommended measures for safe handling, storage, and first aid
- Pictograms: red-bordered diamond symbols depicting hazard types like flames, skulls, or exclamation marks
- Manufacturer information: name, address, and phone number of the responsible company
Small containers get some flexibility. Containers holding 100 ml or less can carry a reduced label with just the product identifier, pictograms, signal word, and the manufacturer’s name and phone number, along with a note that full label information is on the outer packaging. Very small containers of 3 ml or less may only need the product identifier if a full label would interfere with normal use.
Safety Data Sheets
Safety data sheets are the detailed reference documents for every hazardous chemical. They follow a standardized 16-section format, and sections 1 through 11 (plus section 16) are mandatory. Sections 12 through 15 cover environmental and regulatory information that falls under other agencies’ jurisdiction, so OSHA doesn’t enforce them, but they’re still typically included.
The first few sections cover what you’d need in an emergency: identification of the chemical, its hazards, what’s in it, and first aid measures. Sections 5 and 6 deal with fires and spills. The middle sections cover safe handling, storage, exposure limits, and what protective equipment to use. Later sections get into the chemical’s physical properties, stability, and toxicity data. The final mandatory section, 16, records when the SDS was last updated.
Employers must make sure every SDS is readily accessible to workers during their shifts. That can mean a physical binder in the work area, a computer terminal, or another system that doesn’t create barriers to access. If a worker wants to look up a chemical they’re using, they should be able to find the SDS without asking permission or waiting.
Employee Training Requirements
Training is required at two points: when an employee first starts a job involving chemical exposure, and whenever a new chemical hazard is introduced to their work area. OSHA doesn’t mandate a specific number of hours or a refresher schedule. The standard instead requires that training be “effective,” which means workers need to actually understand the material, not just sit through a presentation.
Training must cover four areas. First, workers need to know how to detect when a hazardous chemical has been released, whether through monitoring equipment, visual cues, or smell. Second, they need to understand the types of hazards present, including health risks, fire and explosion dangers, and less obvious threats like oxygen displacement or combustible dust. Third, training must explain the protective measures available: emergency procedures, safe work practices, and personal protective equipment. Fourth, workers must learn how the employer’s hazard communication program works in practice, including how to read labels, where to find safety data sheets, and how to use the information in them.
Connection to the Global System
OSHA’s Hazard Communication Standard is aligned with the Globally Harmonized System of Classification and Labelling of Chemicals, commonly called GHS. This is an international framework that standardizes how chemical hazards are classified and communicated worldwide. Before GHS alignment, a chemical shipped to different countries might need entirely different labels and safety documents for each destination, creating confusion and significant costs for manufacturers involved in international trade.
GHS gave the world a single set of criteria for classifying chemicals and a uniform format for labels and safety data sheets. The standardized pictograms, signal words, and hazard statements you see on chemical labels today all come from GHS. OSHA adopted GHS provisions in a 2012 update to the HCS, and a 2024 final rule further aligned the standard with Revision 7 of GHS (published in 2017). That update also addressed practical issues that had come up over the past decade, including the small-container labeling rules and new provisions allowing manufacturers to claim ingredient concentrations as trade secrets using prescribed ranges rather than exact figures.
Who It Applies To
The Hazard Communication Standard applies to any employer in a general industry, construction, or maritime setting where workers may be exposed to hazardous chemicals. This covers far more workplaces than people expect. It’s not limited to chemical plants or laboratories. Auto repair shops, hair salons, cleaning companies, schools, offices with printer toner and cleaning supplies: if hazardous chemicals are present and workers could be exposed, the standard applies.
The consistently high citation rate reflects how broadly the standard reaches and how often employers fall short. Common violations include missing or outdated safety data sheets, containers without proper labels, incomplete written programs, and failure to train employees. These are largely organizational failures rather than technical ones, which means compliance is less about chemistry expertise and more about building a reliable system for tracking chemicals, maintaining documents, and making sure every new hire gets trained before they start working around hazardous materials.