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OSHA term · Glossary

Hazard Communication Standard (HCS)

Verified vs OSHA sources · 2026-10-05

OSHA's standard (29 CFR 1910.1200) requiring that the hazards of all chemicals produced or imported are classified, and that the information is passed to employers and workers through labels, safety data sheets, and training. It is built on six pillars — a written program, a chemical list, labels, SDSs, training, and access — and is aligned with the GHS.

29 CFR 1910.120029 CFR 1910.1200(a)(1)

Also known as: HCS, HazCom, the “Right-to-Know” law

Hazard Communication Standard (HCS) at a glance

  • Consistently #2 on OSHA's Top 10 most-cited list (FY2025) — and the most-cited standard in general industry.
  • Six pillars: written program, chemical inventory, labels, SDSs, training, and access.
  • Manufacturers/importers classify + label + author SDSs; employers run the program, train, and keep info accessible.
  • Construction adopts it via 29 CFR 1926.59; GHS-aligned since 2012, updated to GHS Rev 7 in 2024.

In plain English

The OSHA rule that says: if there are hazardous chemicals in your workplace, your workers have a right to know about them — and you must tell them through labels, safety data sheets, and training. It's why every chemical container carries a GHS label and every chemical has an SDS.

What the source says, in summary

The purpose of this section is to ensure that the hazards of all chemicals produced or imported are classified, and that information concerning the classified hazards is transmitted to employers and employees.
29 CFR 1910.1200(a)(1)Summarized, not quoted: read the source for its operative wording.

In context

An enforcement, recordkeeping, or general-duty concept under the Occupational Safety and Health Act and 29 CFR. These terms define how OSHA inspects, cites, and penalizes employers.

29 CFR Chapter XVII

Where this is written in OSHA's rules

Example

A contractor brings a 5-gallon pail of two-part epoxy onto a jobsite. HazCom in practice: the manufacturer already classified it and shipped it with a GHS label and an SDS; the employer adds it to the chemical inventory, keeps the SDS accessible to the crew, labels any smaller containers it's poured into, and trains workers on its hazards before they open it.

Why it matters

HazCom ranked #2 on OSHA's FY2025 Top 10 most-cited standards — the rule employers most often get wrong. Gaps such as a missing SDS, an unlabeled secondary container, or no training records are exactly what an OSHA compliance officer looks for first.

History & background

OSHA issued the HCS in 1983 for manufacturing, expanded it to all industries in 1987, then aligned it with the UN GHS in the 2012 update (full compliance 2016). The 2024 final rule updates it to GHS Revision 7.

HCS vs. GHS

GHS is the UN's international framework; the HCS (29 CFR 1910.1200) is the US OSHA regulation that adopts GHS and is what's legally enforced. People say “HazCom,” “HCS,” and “Right-to-Know” to mean the same standard.

The six pillars of HazCom (29 CFR 1910.1200)

PillarWhat it requiresCite
Written programA site-specific written HazCom program(e)
Chemical inventoryA list of the hazardous chemicals present(e)(1)(i)
LabelsCompliant labels on shipped + workplace containers(f)
Safety Data SheetsAn SDS for every hazardous chemical, accessible(g)
TrainingEmployee training at assignment + on new hazards(h)
Trade secretsLimited SDS withholding with disclosure rules(i)

Hazard Communication Standard (HCS): frequently asked questions

What are the six requirements of the Hazard Communication Standard?
A written hazard communication program (e), a list/inventory of hazardous chemicals (e)(1)(i), compliant container labels (f), a safety data sheet for each hazardous chemical (g), employee training (h), and trade-secret provisions (i).
Who has to comply with HazCom?
Chemical manufacturers and importers must classify hazards, label containers, and prepare SDSs. Employers with hazardous chemicals must maintain a written program, keep SDSs accessible, label workplace containers, and train employees. Construction follows the same rule via 29 CFR 1926.59.
Is HazCom the same as Right-to-Know?
Yes — “Right-to-Know” is the common nickname for the Hazard Communication Standard, reflecting workers' right to know the hazards of the chemicals they work with.

Related terms

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Governing OSHA standards

More OSHA terms

Abatement

The action an employer takes to fix a cited violation or eliminate a hazard OSHA identified during an inspection. The citation sets an abatement date, the deadline to correct the hazard, and within 10 calendar days after that date the employer must certify to OSHA that the violation was abated. Failure to abate accrues additional penalties of up to $16,550 per day.

Area Director

The senior OSHA official in charge of a specific OSHA Area Office — the local unit that runs inspections and enforcement in its geographic territory. The Area Director has the authority to issue citations, propose penalties, hold informal conferences with employers, and approve settlement agreements. When a Compliance Safety and Health Officer (CSHO) completes an inspection, it's the Area Director who ultimately issues the citation.

Bureau of Labor Statistics (BLS)

The federal statistical agency within the U.S. Department of Labor that collects, analyzes, and publishes data on workplace injuries, illnesses, and fatalities. BLS conducts the annual Survey of Occupational Injuries and Illnesses (SOII) — compiled from employer OSHA 300 logs — and the Census of Fatal Occupational Injuries (CFOI). SOII data drives OSHA's Site-Specific Targeting (SST) program: establishments whose DART rates significantly exceed their BLS industry average are placed on the SST inspection list.

Competent Person

Under OSHA's construction standards, a person who is capable of identifying existing and predictable hazards in the surroundings or working conditions, and who has the authorization to take prompt corrective measures to eliminate them. The role requires both knowledge and the authority to act, and is mandated by name in many specific standards — excavations, scaffolds, fall protection, asbestos, and more.

Citation

The formal written notice OSHA issues to an employer after an inspection, describing each alleged violation, the standard cited, the proposed penalty, and the date by which the hazard must be corrected (abated). OSHA must issue a citation with reasonable promptness and no later than six months after the violation occurred.

Closing Conference

The meeting at the end of an OSHA inspection where the compliance officer confers with the employer and informally advises them of any apparent violations found. Importantly, the closing conference discusses what was observed and the employer's rights — but it does NOT state final citations or penalties, which come later in the written Citation and Notification of Penalty.

Compliance Officer (CSHO)

An OSHA Compliance Safety and Health Officer — the inspector who conducts workplace inspections. A CSHO presents credentials (a photo ID and a serial number), holds the opening conference, performs the walkaround, collects evidence, interviews employees, and recommends citations. CSHOs are either safety specialists or industrial hygienists.

Contest

An employer's formal challenge to an OSHA citation, penalty, or abatement date. To contest, the employer must file a written Notice of Contest with the OSHA Area Director within 15 working days of receiving the Citation and Notification of Penalty. Filing sends the case to the independent Occupational Safety and Health Review Commission (OSHRC); missing the deadline makes the citation a final, un-appealable order.

Sources & verification

Reviewed by HazComFast against eCFR, OSHA.gov, NIOSH, and the Federal Register. Last reviewed 2026-10-05. This glossary is general information, not legal advice; OSHA State-Plan states (e.g. California, Michigan) may adopt stricter requirements.

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