Everything You Need to Know About Hazard Communication (HazCom)

Every day, millions of workers handle hazardous chemicals — solvents, corrosive cleaners, compressed gases, flammable liquids — and exposure can cause anything from skin irritation to chronic illness and fatal accidents. Hazard communication exists to prevent that harm by guaranteeing every worker the right to know and understand the hazards of the chemicals they work with. It's also a legal requirement under OSHA's Hazard Communication Standard (29 CFR 1910.1200), one of the most frequently cited OSHA standards year after year. This guide breaks down what hazard communication is, what the standard requires, who must comply, and how to build a compliant program.

What Is Hazard Communication?

Hazard communication (often shortened to "HazCom") is the system of identifying chemical hazards in the workplace and communicating those hazards — and the appropriate protective measures — to employees. It rests on the "right to know," which has evolved into the "right to understand": workers are entitled not only to access hazard information, but to receive it in a format they can comprehend and act on.

In practice, the information flows downstream: manufacturers evaluate the hazards of their products, standardized container labels and safety data sheets (SDSs) carry that information forward, and employers translate it into workplace-specific protections — a written program, a chemical inventory, in-house labeling, and training. When the system works, a worker who picks up an unfamiliar container can identify within seconds what it is, what harm it can cause, and what precautions to take. When it fails, workers are left guessing, and guessing with chemicals leads to injuries that are almost entirely preventable.

Hazard Communication vs. Hazardous Communication

You'll occasionally see "hazardous communication" used interchangeably with hazard communication. The correct term is hazard communication — it's communication about hazards — but both phrases refer to the same OSHA framework.

What Is the OSHA Hazard Communication Standard?

The OSHA Hazard Communication Standard (HCS), codified at 29 CFR 1910.1200 and sometimes called the "Right-to-Know" law, is the federal regulation that mandates hazard communication in American workplaces. It requires manufacturers and importers to classify the hazards of the chemicals they produce or import, and requires all employers to inform employees about the hazardous chemicals they may be exposed to.

From Right-to-Know to Right-to-Understand

OSHA first issued the standard in 1983 for manufacturing, expanding it to nearly all industries in 1987. For decades, manufacturers could convey hazard information in any format, producing inconsistent labels and material safety data sheets (MSDSs). That changed in 2012, when OSHA aligned the HCS with the United Nations' Globally Harmonized System of Classification and Labelling of Chemicals (GHS), introducing standardized pictograms, signal words, hazard statements, and a uniform 16-section safety data sheet; a 2024 update aligned it further with GHS Revision 7. Standardization is why professionals describe the modern rule as a shift from the "right to know" to the "right to understand": a worker trained to read one GHS label or SDS can read them all.

The Hazard Communication Standard Includes Which of the Following? Core Elements Explained

A common question on safety exams asks: "The hazard communication standard includes which of the following?" The answer: the HCS is built on five core elements, and a compliant program must address all of them.

1. Hazard Classification

Chemical manufacturers and importers must evaluate every chemical they produce or import and classify its hazards according to the standard's criteria — physical hazards (flammability, reactivity, corrosion of metals), health hazards (acute toxicity, carcinogenicity, sensitization), and hazards not otherwise classified. Each hazard is assigned a class and severity category, and that classification drives everything on the label and SDS.

2. Written Hazard Communication Program

Every employer with hazardous chemicals on site must develop, implement, and maintain a written program describing how it will meet the labeling, SDS, and training requirements at that specific worksite, including a complete chemical inventory and procedures for non-routine tasks and unlabeled pipes.

3. Labels and Other Forms of Warning

Every shipped container must carry six standardized elements: a product identifier, signal word, hazard statement(s), pictogram(s), precautionary statement(s), and supplier contact information. Employers must keep those labels intact and legible, and must label workplace (secondary) containers with either the full GHS label or a product identifier plus words, pictures, or symbols conveying the hazards.

4. Safety Data Sheets (SDSs)

Manufacturers and importers must prepare an SDS in the standardized 16-section format for every hazardous chemical, and employers must keep one for each chemical in the workplace, readily accessible on every shift. "Readily accessible" means no barriers: if workers must ask for a key or a password, the employer isn't compliant.

5. Employee Information and Training

Employers must train workers at initial assignment and whenever a new chemical hazard is introduced. Training covers the standard itself, the location of the written program and SDSs, how to detect a release, the specific hazards in the work area, protective measures, and how to read labels and SDSs — all delivered in a language and manner employees actually understand.

Who Must Comply with the Hazard Communication Standard?

The HCS applies to any workplace where employees may be exposed to hazardous chemicals under normal conditions or in a foreseeable emergency — far more than chemical plants. Manufacturing facilities, construction sites, auto shops, hospitals, laboratories, janitorial services, salons, and warehouses all commonly qualify.

Responsibilities split by role. Manufacturers and importers must classify hazards, author compliant SDSs, and produce GHS shipped labels, updating SDSs within three months and labels within six months of learning new hazard information. Distributors pass labels and SDSs downstream. Employers maintain the written program and inventory, keep labels legible, ensure SDS access, and train employees — and on multi-employer worksites, describe how they'll share hazard information with contractors.

Exemptions exist for EPA-regulated hazardous waste, articles (items that don't release chemicals in normal use), food and cosmetics for personal employee use, and consumer products used the way a typical consumer would use them. That last one trips up many employers: dish soap in the breakroom is exempt, but the same product used in industrial quantities all shift is not.

Reading a GHS Label: The Six Required Elements

The product identifier links the container to its SDS and must match it exactly, while supplier information gives workers and responders a direct line to the source. One of two signal words appears based on the most serious hazard: "Danger" for more severe hazards, "Warning" for less severe ones.

Pictograms are the red-bordered diamonds with black symbols. OSHA mandates eight of the nine GHS pictograms: flame (flammables), flame over circle (oxidizers), exploding bomb (explosives), corrosion, gas cylinder (gases under pressure), skull and crossbones (acute toxicity), health hazard (carcinogens and other serious effects), and exclamation mark (irritants). The ninth, the environment pictogram, falls outside OSHA's jurisdiction.

Hazard statements are standardized phrases describing the nature and degree of the hazard, such as "Causes serious eye damage." Precautionary statements describe measures for prevention, response, storage, and disposal. Because the wording is standardized, the same hazard reads the same way on every compliant label in every workplace.

The 16 Sections of a Safety Data Sheet

The GHS-aligned SDS uses a fixed structure so workers always know where to look: (1) Identification, (2) Hazard identification, (3) Composition and ingredients, (4) First-aid measures, (5) Fire-fighting measures, (6) Accidental release measures, (7) Handling and storage, (8) Exposure controls and personal protection, (9) Physical and chemical properties, (10) Stability and reactivity, (11) Toxicological information, (12) Ecological information, (13) Disposal considerations, (14) Transport information, (15) Regulatory information, and (16) Other information. Sections 2, 4, 7, and 8 do the heaviest lifting in daily use — hazards, emergency response, handling and storage, and required controls and PPE — while sections 12–15 fall under other agencies and aren't enforced by OSHA.

How to Build an Effective Hazard Communication Program

A strong program treats the five elements as a living system rather than a binder on a shelf.

Step 1: Assign Responsibility and Take Inventory

Designate an owner, then walk the entire facility — storage rooms, maintenance closets, vehicles, loading docks — and list every hazardous chemical present, recording product identifiers exactly as they appear on labels. This inventory becomes the backbone of the program.

Step 2: Collect and Organize Safety Data Sheets

Obtain a current SDS for every item on the inventory, documenting any written requests to manufacturers. Organize the library so any employee can find any sheet in seconds, and keep it current as chemicals change.

Step 3: Write the Site-Specific Program

Draft the written program covering labeling, SDS access, training, non-routine tasks, unlabeled pipes, and multi-employer coordination. Keep it site-specific — a generic template won't satisfy an OSHA inspector.

Step 4: Audit Your Labels

Verify shipped containers retain their original labels and every secondary container — spray bottles, dip tanks, transfer jugs — carries compliant labeling. The lone exception is a portable container filled for the immediate, same-shift use of the employee who fills it.

Step 5: Train, Verify, and Repeat

Deliver training specific to your chemicals and tasks, verify comprehension rather than attendance, retrain whenever a new hazard enters the workplace, and document who was trained, when, on what, and by whom.

Common Hazard Communication Violations

HazCom violations follow predictable patterns: no written program at all, untrained employees, missing or inaccessible safety data sheets, unlabeled secondary containers, and inventories that no longer match the shelves. The fix is disciplined housekeeping — review the program annually, reconcile the inventory on a schedule, spot-check containers during walkthroughs, and tie training records to onboarding. Penalties can reach tens of thousands of dollars per citation, but the real cost of poor hazard communication is measured in chemical burns, respiratory disease, and lives.

Frequently Asked Questions About Hazard Communication (HazCom)

What is hazard communication (HazCom)?

Hazard communication is the comprehensive system for identifying the hazards of workplace chemicals and transmitting that information to the people who may be exposed to them. It encompasses the entire chain of information flow: chemical manufacturers classify the physical and health hazards of their products; that information travels downstream through standardized container labels and 16-section safety data sheets; and employers complete the chain by maintaining a written program, keeping an accurate chemical inventory, labeling workplace containers, providing ready access to safety data sheets, and training employees on the specific hazards in their work areas. The underlying philosophy is often called the "right to understand" — the idea that workers are entitled not just to have hazard information available somewhere, but to receive it in a standardized, comprehensible format they can act on in real time. In the United States, hazard communication is mandated by OSHA's Hazard Communication Standard, 29 CFR 1910.1200, which applies to virtually every workplace where employees may be exposed to hazardous chemicals during normal operations or foreseeable emergencies.

What is the Hazard Communication Standard?

The Hazard Communication Standard (HCS) is the OSHA regulation, found at 29 CFR 1910.1200, that legally requires hazard communication in American workplaces. Often called the "Right-to-Know" law, it imposes two sets of obligations. First, chemical manufacturers and importers must evaluate the chemicals they produce or import, classify their hazards according to defined criteria, and communicate those hazards through GHS-compliant shipped labels and standardized safety data sheets. Second, all employers with hazardous chemicals in their workplaces must implement a written hazard communication program, maintain a chemical inventory, ensure containers are properly labeled, keep safety data sheets readily accessible to employees on every shift, and provide effective training. The standard was first issued in 1983, was aligned with the UN's Globally Harmonized System (GHS) in 2012 to standardize label elements and the SDS format, and was updated again in 2024 to incorporate GHS Revision 7. Because it touches nearly every industry, the HCS is one of the most frequently cited OSHA standards during inspections.

What is the primary purpose of the Hazard Communication Standard?

The primary purpose of the Hazard Communication Standard is to ensure that the hazards of all chemicals produced in or imported into the United States are classified, and that information about those hazards is transmitted to affected employers and exposed employees. In simpler terms, its purpose is to guarantee that no worker handles a hazardous chemical without knowing what it is, what harm it can cause, and how to protect themselves. The standard accomplishes this by creating an unbroken chain of standardized communication that follows a chemical from its point of manufacture to its point of use: hazard classification at the source, uniform labels and safety data sheets in transit, and written programs plus training at the workplace. A secondary but important purpose of the GHS-aligned standard is consistency — by requiring the same pictograms, signal words, hazard statements, and 16-section SDS format everywhere, it reduces confusion, improves comprehension for workers across industries and language backgrounds, and facilitates international trade in chemicals. Effective hazard communication is widely credited with preventing large numbers of chemical-related fatalities, injuries, and illnesses every year.

What is a hazard communication program?

A hazard communication program is the written, site-specific plan that describes how a particular employer meets each requirement of the Hazard Communication Standard. Every employer with hazardous chemicals in the workplace must develop, implement, and maintain one. At minimum, the written program must address three core areas: how the employer handles container labeling and other forms of warning; how safety data sheets are obtained, maintained, and made readily accessible to employees; and how employee information and training are delivered. The program must also include a complete inventory of the hazardous chemicals known to be present at the worksite (using product identifiers that match the labels and SDSs), procedures for informing employees about the hazards of non-routine tasks such as tank cleaning or maintenance work, and procedures for communicating the hazards of chemicals contained in unlabeled pipes. On multi-employer worksites, the program must additionally explain how hazard information and SDS access will be shared with contractors and other employers whose workers may be exposed. The program must be available on request to employees, their representatives, and OSHA — and it must reflect what actually happens on site, because a generic template that doesn't match real practices is itself a compliance failure.

What is the purpose of the OSHA Hazard Communication Standard's alignment with GHS?

OSHA aligned the Hazard Communication Standard with the United Nations' Globally Harmonized System of Classification and Labelling of Chemicals in 2012 to solve a persistent problem: inconsistency. Before alignment, manufacturers could present hazard information in any format they chose, producing material safety data sheets that ranged from one page to fifty, organized in no particular order, and labels whose warnings varied from supplier to supplier for the identical chemical. Workers had to relearn where to find critical information with every new product. GHS alignment standardized everything — hazard classification criteria, the nine pictograms, the two signal words ("Danger" and "Warning"), the wording of hazard and precautionary statements, and the fixed 16-section safety data sheet format. The purpose was to transform the "right to know" into the "right to understand": once a worker learns to read one GHS label and one SDS, they can read them all, regardless of manufacturer, industry, or country of origin. The alignment also harmonized U.S. requirements with those of major trading partners, reducing compliance burdens for companies shipping chemicals internationally. OSHA's 2024 update, incorporating GHS Revision 7, continued this work by refining classification criteria and clarifying label requirements for small containers.

Final Thoughts

Hazard communication is one of the highest-leverage safety management systems any organization can invest in, because it multiplies across every chemical, task, and worker on site. The requirements are straightforward on paper, but sustained compliance takes ownership, regular audits, and training that prioritizes genuine understanding over checkbox completion. Get those pieces right, and you don't just avoid one of OSHA's most common citations — you give every employee the knowledge to go home healthy at the end of every shift.