OSHA's Hazard Communication Standard [CFR 1910.1200]

CLICK HERE OSHA's Hazard Communication Standard [CFR 1910.1200]:

Under the Hazard Communication Standard (HCS), chemical manufacturers and importers must research the chemicals they produce and import. If a substance presents any of the physical and health hazards, as specified in the HCS, then the manufacturer or importer must communicate the hazards and cautions to their employees as well as to "downstream" employers who purchase the hazardous chemical. The goal behind the HCS is a safer workplace for workers, who informed of the hazards they encounter on the job, can create a safer work environment.

Employer failure to comply with the Hazard Communication Standard
causes the most OSHA citations. 50% of OSHA's citations relate to a failure
to implement the Hazard Communication Standard.

Protection under OSHA's Hazard Communication Standard (HCS) includes all workers exposed to hazardous chemicals in all industrial sectors. Employees have both a need and a right to know about the identities and the hazards of the chemicals they are exposed to in the workplace. Employees also need to know what protective measures are available to prevent adverse effects from occurring. More than 30 million workers are potentially exposed to one or more chemical hazards. There are an estimated 650,000 existing hazardous chemical products, and hundreds of new ones are being introduced annually. The (HCS) covers both physical hazards (such as flammability or the potential for explosions), and health hazards (including both acute and chronic effects). By making information available to employers and employees about these hazards, and recommended precautions for safe use, proper implementation of the HCS will result in a reduction of illnesses and injuries caused by chemicals. Using HCS, employers will have the information they need to design an appropriate protective program for their employees. Employees will be better able to participate in these programs effectively when they understand the hazards involved, and how and what steps to take to protect themselves. Together, these employer and employee actions will help prevent the occurrence of adverse effects caused by the use of chemicals in the workplace.

The HCS established uniform requirements to make sure that the hazards of all chemicals imported into, produced, or used in U.S. workplaces are evaluated and that this hazard information is transmitted to affected employers and exposed employees.

Chemical manufacturers and importers must convey the hazard information they learn from their evaluations to downstream employers by means of labels on containers and Material Safety Data Sheets (MSDSs). In addition, all covered employers must have a hazard communication program to get this information to their employees through labels on containers, MSDS's, and employee training.

This hazard communication program ensures that all employers receive the information they need to inform and train their employees properly, and to design and put in place employee protection programs. It also provides necessary hazard information to employees so they can participate in and support the protective measures in use at their workplaces. Employees are often the best source of suggestions about how to reduce workplace hazards and chemical exposures, which can also translate into cost cutting and savings.

All employers, in addition to those in manufacturing and importing, are responsible for informing and training workers about the hazards in their workplaces, retaining warning labels, and making available MSDS's with hazardous chemicals.

Some employees deal with chemicals in sealed containers under normal conditions of use (such as in the retail trades, warehousing, truck and marine cargo handling). Employers of these employees must assure that labels affixed to incoming containers of hazardous chemicals are kept in place. They must maintain and provide access to MSDS's received, or obtain MSDS's if requested by an employee. And they must train workers on what to do in the event of a spill or leak. However, written hazard communication programs will not be required for this type of operation.

All workplaces where employees are exposed to hazardous chemicals must have a written plan which describes how the standard will be implemented in that facility. The only work operations that do not have to comply with the written plan requirements are laboratories and work operations where employees only handle chemicals in sealed containers. Workers must still be trained about what to do in the event of a spill or leak, however.

The written program must reflect what employees are doing in a particular workplace. For example: the written program must list the chemicals present at the site, indicate who is responsible for the various aspects of the program in that facility, and where written materials (MSDSs) will be made available to employees.

The HCS mandates the following:



The Occupational Safety and Health Administration (OSHA) is responsible for issuing standards and rules for safe and healthful working conditions, tools, equipment, facilities, and processes. Employers have the general duty of providing their workers a place of employment that is free from recognized hazards to safety and health, a place of employment which must comply with OSHA standards. OSHA sets chemical exposure limits called Permissible Exposure Limits (PEL). But these OSHA PELs have been known to be wrong before. For example, Methylene Chloride once had an OSHA PEL of 500 parts per million (PPM), and now, over a period of ten years, that PEL has been revised downward to 25 PPM. 1,3 Butadiene once had an OSHA PEL of 1,000 PPM, and this has now been reduced to 1 PPM.

OSHA PELs are based on the concept that the worker is exposed to chemicals for no more than eight hours at a time. The worker has "downtime," or time away from the chemicals and workplace, allowing the body time to remove or lower the amount of chemicals in the system. Continuous exposure with no downtime does not allow for the body to cleanse itself, therefore continuous exposure limits can cause the body to accumulate the chemical at a greater rate than it can expel it, a potentially dangerous situation. OSHA PELs do not apply to continuous exposure. Firefighters responding to a chemical spill or release should determine the OSHA PEL for the chemical spilled and consider the "safe" zone for the public to be at 1/100th or 1/1,000th the OSHA PEL. There may be quite a problem in determining exactly what chemical has been spilled, so this task for firefighters is not easy. Often, there will be many chemicals in the workplace, and the interactions of these make assessing the hazard very difficult for firefighters and emergency responders, especially if a fire is involved, which can create new substances and chemical combinations.

The firefighters responding to a chemical spill or release often consider or use another standard, the IDLH, or Immediately Dangerous to Life or Health. What the IDLH level is also helps emergency responders determine whether to use a respirator, or what types of respirator, to use in a response. Obviously, knowing what these different standards are, what they mean, and how to interpret them is something to be done long before any accident occurs. This is another reason why chemical emergency preparedness depends on real-time, valid facility chemical inventory information.


Click here to go to the NIOSH page to get NIOSH publications.

To further complicate matters, the OSHA PEL may not be an entirely correct figure. The National Institute of Occupational Safety and Health (NIOSH) has created standards for exposure to chemicals with Recommended Exposure Limits (REL) that are usually below OSHA PEL standards. And the American Conference of Governmental Industrial Hygienists (ACGIH) has created standards named Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) that are also generally below OSHA PEL levels.

NIOSH Recommended Exposure Limits (REL) are developed under the authority of the Occupational Safety and Health Act of 1970 (29 USC Chapter 15) and the Federal Mine Safety and Health Act of 1977 (30 USC Chapter 22). NIOSH develops and periodically revises recommended exposure limits( RELs) for hazardous substances or conditions in the workplace. NIOSH also recommends appropriate preventive measures to reduce or eliminate the adverse health and safety effects of these hazards. To formulate these recommendations, NIOSH evaluates all known and available medical, biological, engineering, chemical, trade, and other information relevant to the hazard. These recommendations are then published and transmitted to OSHA and Mine Safety and Health Administration (MSHA) for use in promulgating (creating) legal standards. The operative word here is "recommend." NIOSH is purely an advisory body and has no legal authority of its own. OSHA is the only agency who has the legal authority to set exposure standards. The main difference between OSHA and NIOSH is that OSHA uses an eight hour time-weighted average while NIOSH uses a 10 hour time-weighted exposure limit. [Time-weighted average means averaged over a period of time, so higher and lower exposure levels can occur.] [LINK http://www.cdc.gov/niosh/pubs.html]

Also, NIOSH sets "ceilings" for which exposure levels cannot be exceeded at any time. OSHA rarely sets any "ceiling" exposure levels. OSHA is not always successful in implementing NIOSH's recommendations: In July 1992, the 11th Circuit Court of Appeals in its decision in AFL-CIO v. OSHA, 965 F.2d 962 (11th Cir., 1992) vacated more protective PELs set by OSHA in 1989 for 212 substances, moving them back to PELs established in 1971. http://www.cdc.gov/niosh/npg/npg.html

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) refer to airborne concentrations of substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed day after day without adverse health effects. These exposure levels are based on animal studies. With these and with all such exposure standards, there is uncertainty, and not a guarantee that adverse health will not result from exposure to these levels of chemicals in the air.

There are other related terms and abbreviations that may be encountered. STELs, which are Short-Term Exposure Levels (15 minutes), are based on the theory that a short-term exposure to certain levels of certain chemicals may be allowed. For the vast majority of chemicals, there is simply not enough toxicological data to warrant or establish a STEL. TWA stands for Time-Weighted Average, which is based on the idea that exposure to levels of chemicals above the Threshold Limit Values are allowed so long as the employee is subjected to periods of time when the exposure to levels of chemicals is below the Threshold Limit Values during the workday. Biological Exposure Indices (BEIs) are reference values intended as guidelines for the evaluation of potential health hazards in the practice of industrial hygiene. BEIs represent the levels of determinants which are most likely to be observed in specimens collected from a healthy worker who has been exposed to chemicals to the same extent as a worker with some inhalation exposure to the TLV.


  1. OSHA Permissible Exposure Limits:
    Eight hour time-weighted average concentration
    15 minute time-weighted average concentration
    Ceiling concentration - not to be exceeded
  2. NIOSH Recommended Exposure Limits:
    Eight hour time-weighted average concentration
    15 minute time-weighted average concentration
    Ceiling concentration - not to be exceeded
    30 minute concentration that is Immediately Dangerous to Life and Health
  3. ACGIH recommended Treshold Limit Values:
    Eight hour time-weighted average concentration
    15 minute time-weighted average concentration
    Ceiling concentration - not to be exceeded
  4. IDLH - Immediately Dangerous to Life or Health
    The maximum level from which a worker could escape without any irreversible health effects within a 30 minute time-frame.

But these OSHA PELs have been known to be wrong before. For example, Methylene Chloride once had an OSHA PEL of 500 parts per million (ppm), and now, over a period of ten years, that PEL has been revised downward to 25 ppm. 1,3 Butadiene once had an OSHA PEL of 1,000 ppm, and this has now been reduced to 1ppm.


Hazardous materials can pose both short-term and possibly long-term toxicological threats to human life and health.


Chemicals - solids, liquids, or gases/vapors can affect humans by primary routes of entry such as:

Inhalation exposures may result from breathing gases, vapors, aerosols, or particulates.

Ingestion (i.e., oral) exposures may follow from poor hygiene practices after handling of contaminated materials or from ingestion of contaminated food or water. Ingestion may also occur following inhalation of insoluble particles that become trapped in mucous membranes and swallowed after being cleared from the respiratory tract. (Workers may even "taste" chemicals after inhaling them.)

Direct skin contact may result from exposures to hazardous gases, liquids or solids in the environment, either on land, in the air, or in water. Effects may be local and involve irritation or burns of the skin or eyes or involve poisoning via absorption through external bodily tissues. The worker may not be aware of this exposure for some time.

There are various specific gases, liquids, and even solid materials which have the capability of passing through the skin or tissues of the eyes at various rates upon contact. Those that are highly toxic and which penetrate the body rapidly are the most hazardous. Those that penetrate slowly or which are of relatively low toxicity may require long term contact with large parts of the body to cause significant effects. Although some materials may give some warning that contact has occurred by causing some sort of burning sensation, others may give little or no warning to the victim.

Chemicals considered highly toxic means that relatively small quantities may cause significant health effects upon inhalation, ingestion, and/or direct contact. Chemicals considered to be of low toxicity generally requires larger amounts to be inhaled, ingested, or contacted for an equally significant adverse health effect.

It is therefore prudent to always remember that a large quantity of a low toxicity material may present the same or greater toxic hazard to a person than a much smaller quantity of a highly toxic material. It is also necessary to understand that the toxicity of a material is only one of several factors to be considered in determining the toxic hazard posed by the material.