3.1 Hazard Communication Standard (29 CFR 1910.1200) & GHS

The OSHA Hazard Communication Standard (HCS), codified in 29 CFR 1910.1200, is one of the most frequently cited standards in general industry. Often referred to as "HazCom," its primary purpose is to ensure that the hazards of all chemicals produced or imported are evaluated, and that information concerning their hazards is transmitted to employers and employees.

Historically, the HCS was known as the "Right to Know" standard. However, in 2012, OSHA aligned the HCS with the United Nations' Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Revision 3. This transition represented a major shift from simply providing information ("Right to Know") to ensuring that employees comprehend the information ("Right to Understand"). By standardizing chemical classification, labels, and safety data sheets across the globe, HazCom 2012 reduces confusion, prevents workplace injuries and illnesses, and facilitates international chemical trade.

Failure to maintain a written HazCom program is one of the top five most frequently cited OSHA violations. As of 2026, OSHA penalty tiers allow for fines up to $16,131 for a single Serious violation, and up to $161,323 for a Willful or Repeated violation.

Scope of the Standard

The standard applies to any chemical that is known to be present in the workplace in such a manner that employees may be exposed under normal conditions of use or in a foreseeable emergency. The responsibilities under HazCom are divided into distinct tiers:

1. Chemical Manufacturers and Importers: Must evaluate the chemicals they produce or import to determine their classification as physical or health hazards. They are responsible for creating Safety Data Sheets (SDSs) and primary container labels.
2. Distributors: Must ensure that SDSs and appropriate labels are passed along to downstream employers.
3. Employers: Must establish a comprehensive, written Hazard Communication program for their employees, ensure all containers are labeled, make SDSs accessible, and train workers on the hazards and protective measures.

GHS Alignment and Hazard Classification

Under GHS, chemical hazards are classified into specific categories based on the severity of the hazard. A critical aspect of this system is that Category 1 always represents the most severe hazard, with higher numbers (e.g., Category 2, 3, or 4) representing progressively less severe hazards. This is inverse to some traditional rating systems, such as the NFPA 704 system, where 4 is the most severe hazard. On the OSHA exam, this distinction is highly testable.

For mixtures of chemicals, manufacturers must follow strict classification thresholds. If a mixture contains a health hazard (such as a skin irritant or target organ toxin) at a concentration of 1.0% or more, the mixture must be classified as possessing that hazard. However, if the component is a carcinogen, germ cell mutagen, or reproductive toxicity agent, the threshold drops to 0.1% or greater to trigger classification.

The HCS divides chemical hazards into two broad groups: physical hazards and health hazards.

Physical Hazards

A chemical is classified as a physical hazard if there is scientifically valid evidence that it is a combustible liquid, a compressed gas, explosive, flammable, an organic peroxide, an oxidizer, pyrophoric, unstable (reactive), or water-reactive.

• Flammable Liquids: Classified based on flashpoints and boiling points. For instance, Category 1 flammable liquids have a flashpoint below 23 degrees C (73.4 degrees F) and a boiling point at or below 35 degrees C (95 degrees F).
• Pyrophorics: Chemicals that ignite spontaneously in air at or below 54.4 degrees C (130 degrees F).
• Oxidizers: Chemicals that initiate or promote combustion in other materials, causing fire either of itself or through the release of oxygen.

Health Hazards

A chemical is classified as a health hazard if exposure can produce acute or chronic harmful effects on the body. Health hazards include:

• Acute Toxicity: Refers to adverse effects occurring following oral, dermal, or inhalation exposure to a single dose, or multiple doses within 24 hours. Classified into five categories based on lethal dose (LD50) or lethal concentration (LC50) values.
• Skin Corrosion/Irritation: Skin corrosion is the production of irreversible damage to the skin (visible necrosis) following the application of a test substance for up to 4 hours. Skin irritation is reversible damage.
• Carcinogenicity: Chemicals that induce cancer or increase its incidence. Mixture rules state that if a mixture contains a classified carcinogen at a concentration of 0.1% or greater, the entire mixture must be classified as a carcinogen. For other health hazards, the threshold is typically 1.0%.
• Mutagenicity, Reproductive Toxicity, and Target Organ Toxicity: These represent chronic health hazards that can cause genetic mutations, damage reproductive organs/fetuses, or target specific organs like the liver (hepatotoxins) or kidneys (nephrotoxins).

Written Hazard Communication Program Requirements

Employers must develop, implement, and maintain a written, comprehensive hazard communication program at each workplace. The written program must be accessible to all employees, their designated representatives, and OSHA inspectors during all shifts. A complete program must contain the following core elements:

1. Chemical Inventory: A complete list of all hazardous chemicals known to be present in the workplace. This list must use a product identifier that aligns exactly with the identifier used on the Safety Data Sheet (SDS) and the container label. This allows workers to easily cross-reference the inventory with the detailed hazard information.
2. Labels and Other Forms of Warning: The program must document how the employer will meet labeling requirements for all containers, including primary manufacturer containers, secondary (in-house) containers, and how warnings will be managed for stationary process vessels (like tanks or vats).
3. Safety Data Sheets (SDSs): The written program must describe how the employer will obtain, maintain, and ensure immediate access to SDSs for every hazardous chemical in the workplace. Employees must not face barriers (such as needing to ask a supervisor or use a locked computer) to access SDSs during their shift.
4. Employee Information and Training: The program must detail the training plan. Employers must train employees on hazardous chemicals in their work area at the time of their initial assignment and whenever a new physical or health hazard is introduced into their work area. Training must cover:
   • The requirements of 29 CFR 1910.1200.
   • Workplace areas where hazardous chemicals are present.
   • How to detect the presence or release of a chemical (e.g., monitoring devices, odor, visual appearance).
   • The physical, health, simple asphyxiation, combustible dust, and pyrophoric gas hazards of the chemicals.
   • Protective measures, including specific procedures implemented by the employer (engineering controls, work practices, and PPE).
   • Details of the hazard communication program, including how to read labels and SDSs.
5. Multi-Employer Worksites: On worksites where employees of more than one employer are performing tasks (such as construction sites or contracted maintenance in a factory), the written program must outline how SDSs will be shared, how precautionary measures will be communicated, and how the labeling system will be explained to other employers' workers.