Health & Safety

Hazard Communication

The Hazard Communication Program also known as HazCom aims to safeguard individuals from accidents and diseases caused by the use of hazardous substances in the workplace. People have the right to know and comprehend the risks and identities of the substances to which they are exposed at work.

By law, you have a right to know how to protect yourself from the hazards that may exist in your workplace. Information about these hazards is provided by warning labels, documents, and training.

The Hazard Communication is a reference tool that you can use to reinforce your understanding of how to obtain information about workplace hazards.

Hazard Communication is divided into four parts:

  • Written HAZCOM Program
  • Types of Hazards
  • Warning Labels
  • Material Safety Data Sheets

“Written HAZCOM Program” describes the basic purpose and content of a written hazard communication program and explains how workers typically obtain the information and training that are identified in such a program.

“Types of Hazards” defines and gives examples of physical hazards, health hazards, acute health effects, and chronic health effects that can be associated with hazardous chemicals.

“Warning Labels” describes labeling requirements for hazardous substances in the workplace and explains how to interpret information on an NFPA fire diamond and an HMIS® label.

“Material Safety Data Sheets” describes the types of information typically found on Material Safety Data Sheets.

Written Hazcom Program

This part describes the basic purpose and content of a written hazard communication (HAZCOM) program. It also identifies typical means by which workers can obtain the information and training that are specified in their facility’s HAZCOM program.


Whenever you are assigned to a work area where you will be exposed to hazardous chemicals or whenever a new chemical hazard is introduced into your work area, your employer will inform you about exactly what hazards are posed by these chemicals and what you will need to do to minimize your risk of exposure.

Information about hazardous chemicals is provided in your facility’s written hazard communication (HAZCOM) program. The written program is available to all personnel, including contract workers and visitors, who may be exposed to hazardous chemicals.


In the written program, you can find out what hazardous chemicals are present in your workplace, the specific hazards these chemicals pose, and what training is required to enable you to deal with the chemicals safely.

The format of a written HAZCOM program can vary from one facility to another, but the essential content is the same.

Topics that are covered in the written program include the identity and location of hazardous chemicals in the facility; the labeling system or systems that are used to label hazardous chemicals; and how to obtain Material Safety Data Sheets for hazardous chemicals and interpret the information these forms contain.


The program must also specify the information and training that are required for all personnel who must work with or around hazardous chemicals, and it must describe how the information and training are provided.


Hazard communication training is an ongoing task. Whenever new hazardous chemicals are introduced into your workplace, your facility’s written HAZCOM program is updated to include safety precautions and handling procedures for the new chemicals.

If a process change involves a new hazardous chemical, all employees, including contract or other temporary workers, will be provided with information and training about the new hazard and how to protect themselves from it.


Typically, much of the information and training that are specified in your facility’s written HAZCOM program is provided through regularly scheduled safety meetings and formal training classes.


The meetings and classes explain the measures that your employer has taken to protect you from certain hazardous chemicals. For instance, your employer may have put engineering controls in place to minimize your exposure to a chemical hazard.


One example of using engineering controls is putting an exhaust fan in a portable fume extractor to remove hazardous fumes while an arc welding job is underway. When the exhaust fan is in operation, the welder does not need to wear a respirator.


Because of the chronic health effects that can result from prolonged exposure to some chemicals, your employer may have taken measures to ensure that you are not exposed to unsafe levels of these substances.

There may be a local detection system in your work area to provide an audible or a visible warning of an unplanned release.

In one type of detection system, when vapors leak out of compressed gas storage tanks and ignite, a sensor detects ultraviolet light from the flames. Then, an alarm sounds, and a deluge system for the storage tanks is automatically activated.


Learning what the various activated alarms in your workplace sound like and look like is an important part of your HAZCOM training. It could one day save your life.


You may also be required to use a personal exposure monitor to track your long-term exposure to a hazardous chemical. For example, one type of personal exposure monitor is used to measure a worker’s exposure to airborne lead.


Safety meetings and training classes also provide instruction to prepare you to do what you must to ensure your own protection. This includes using required personal protective equipment properly and following appropriate procedures to ensure safe work practices.


Learning how to detect a release of a hazardous chemical and learning what to do in the event of a release are also critical parts of your training.

You may be able to detect a chemical release simply through your senses of sight and smell. In other cases, devices such as gas sniffers are required for leak detection.

In some situations, with appropriate precautions, you can contain a spill or release of a hazardous chemical. In other situations, the safe response is to leave the area immediately. You’ll need to know where to go, how to get there, and what personal protective equipment you need so that you can get out safely.



For chemicals whose vapor densities are less than air, you may be able to avoid hazardous vapors by crawling out of an area.

For chemicals whose vapor densities are greater than air, the vapors tend to concentrate near ground level. So, if there is a release of this type of chemical, it is safer to leave the area by walking upright.


The exact training and information that will be provided to you depend on the nature of the chemicals that you will be working around and the nature of the job that you will be performing.

For non-routine tasks, such as confined space entry or cleaning out a tank, you will need training in the specific procedures and special safety precautions that you must follow.

If unlabeled pipes in your assigned work area carry hazardous chemicals, you will need to be informed about this and trained in what you must do to protect yourself.


If you have questions or concerns about the chemical hazards in your facility, talk with a supervisor or a trainer. When you are working around hazardous chemicals, you have a right to know what you’re dealing with and a responsibility to learn how to protect yourself.

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Types of Hazards

Hazard communication involves making sure that personnel are aware of the hazards that are associated with chemicals in the workplace. Employers are required by law to identify the chemicals in the workplace that could be hazardous and to inform you of the type of hazard that each chemical poses. This part describes two different types of hazards and some of the effects that they can have.


Hazardous chemicals can be classified into two basic categories: substances that pose physical hazards and substances that pose health hazards.


A substance that poses a physical hazard either can destroy living tissue through direct chemical action, or has the potential to catch fire or explode.

For example, a substance may be a physical hazard because it is highly flammable. Basically, flammable substances readily catch fire and burn at a relatively low temperature.

A corrosive substance is also a physical hazard. It can erode living tissue and cause visible, possibly irreversible, damage.

A substance may also be a physical hazard because it is reactive. The term “reactivity” refers to the tendency of a substance to undergo a chemical change, or reaction, that involves a release of energy, such as an explosion.


Reactive substances can explode if they are handled improperly or mixed with certain other chemicals. Also, if they are combined with incompatible chemicals, reactive substances can release gases that may pose health hazards.

A substance that is a health hazard can have a direct effect on a person’s health. Health hazards can cause anything from allergic reactions to disease or damage to bodily tissues and organs.

The effects of health hazards may be acute or chronic.


Typically, acute health effects occur rapidly as a result of short-term exposure to a health hazard, and they last for a relatively short period of time. Some common examples of acute health effects are skin or eye irritation, nausea, vomiting, dizziness, and unconsciousness.


Chronic health effects occur after repeated or long-term exposure to a health hazard. They may not show up until months or years after exposure, and they may have a long duration. Cancer, heart disease, and lung disease are examples of chronic health effects.

Warning Labels

Hazard communication involves labeling containers to identify hazardous substances and provide warnings. This part describes labeling requirements for substances used in the workplace, and explains how to read and interpret labels based on two commonly used labeling systems.


The Occupational Safety and Health Administration (OSHA) requires that all containers of hazardous substances be properly labeled with the name of the substance that is inside the container and any necessary warnings.

Labels on containers that are provided by the manufacturer of the substance must also provide the name and address of the manufacturer.


One exception to the OSHA labeling requirements involves portable storage containers. If a worker transfers a substance from a labeled container to a portable container, so that this same worker can use the substance in the portable container within a single work shift, no label is required on the portable container.

Of course, it is always a good idea to label containers anyway, to avoid the potential for mistakes.

Another good practice is to put only the amount that you need into a portable container, since storing excess substances in portable containers can create an unnecessary safety risk.


If a portable container of a hazardous substance will be used by more than one person, or if it will be used during more than one shift, the portable container must be properly labeled.

Substance warnings can be represented in a number of ways. Some labeling systems use easily recognizable pictographs, while others use symbols and/or words.

Two commonly used types of hazard warning labels are the National Fire Protection Association (NFPA) label and the Hazardous Materials Identification System (HMIS) label.


This is an example of an NFPA label.



This is an example of an HMIS label.



On both NFPA labels and HMIS labels, the blue section is used to provide information about health hazards.


The red section is for information about fire hazards.


The yellow section contains information about reactivity hazards, that is, the tendency of the substance to undergo a chemical change, or reaction, that involves a release of energy, such as combustion or an explosion.


In addition, each of these sections of the labels may contain a number that indicates the severity of the hazard. The numbers range from 0 to 4: the higher the number, the more severe the hazard.


The white section is used differently in the NFPA and HMIS® labeling systems.


The white section of the HMIS label contains letters to indicate what personal protective equipment is required for personnel working with or around the substance.


This section can also be used to indicate the emergency response equipment that should be kept nearby.

The equipment that is indicated by the letter in the white section of the label is typically shown in pictographs on an accompanying chart for the HMIS® labeling system.


The white section of the NFPA label is used to indicate special hazard warnings.

For example, a substance that is corrosive is identified by the letters “COR” in the white section of the NFPA label.


For a substance that reacts with water, the white section of the NFPA label has a “W” with a line through it, which tells you to “use no water” around the substance.



Various warning labels may be used throughout your facility. It is essential to your health and safety on the job that you understand how to interpret the warning labels that you see.

Your employer must provide you with information about the labels used in your facility and how to read them. Take the time to study this information.

If you have any questions about what a warning label means, check with a supervisor or a trainer. Remember, you have a right to know.

Material Safety Data Sheets

Material Safety Data Sheets are one of the most valuable sources of information about the hazardous chemicals used in a facility. This part describes information that is typically found on a Material Safety Data Sheet.


By law, a Material Safety Data Sheet (MSDS) must be maintained on site for every hazardous chemical that is used in a workplace.


While the information on an MSDS can be arranged in a number of different ways, all of these documents contain the same basic information.


A typical MSDS includes sections on the identity of the substance, or product; hazardous ingredients; physical characteristics; fire and explosion data; reactivity data; information about potential health hazards; precautions for safe handling; and control measures, which covers the required personal protective equipment (PPE).

The identification section of an MSDS includes both the common name of the product and its chemical name. This section also includes the name, address, and emergency phone number of the manufacturer of the product. A non-emergency phone number may also be included.

The identification section should also include the date that the MSDS was prepared.


The ingredients section provides a list of hazardous substances that make up the product.


The physical characteristics section provides information about the product’s boiling point, melting point, vapor pressure, vapor density, and solubility in water. Other distinguishable characteristics, such as color and odor, are also indicated.


The fire and explosion data section provides essential information about how the product reacts to heat, the risk of explosion, and how to combat a fire involving the product.

It also lists the proper extinguishing media to use in the event of a fire, as well as any special fire-fighting procedures that should be employed.

Any unusual fire and explosion hazards are also included in this part of the MSDS.


The reactivity data section contains information about the stability of the product. This tells you how easily the product will react with other substances. The reactivity section of the MSDS also lists any conditions and materials that should be avoided when this product is used.


The health hazards section lists risks to your health. This section of the MSDS includes any exposure limits that should be observed when you are working with the product.

Exposure limits are often indicated on an MSDS as the Threshold Limit Value (TLV). You may also see exposure limits indicated as PEL, which stands for OSHA-regulated Permissible Exposure Limits.

The health hazards section typically indicates if the product is a known or suspected carcinogen, or cancer-causing agent.

Also included is information about how the product can enter your body. Inhalation, ingestion, injection, and skin and eye contact are examples of routes of entry.

Symptoms of acute overexposure are listed in the health hazards. These symptoms are immediate effects of sudden overexposure to the substance.

The health hazards section also details symptoms of chronic overexposure to the product and the possible risks of long-term exposure. Medical conditions that can be aggravated by exposure to the product are identified.

Typically, emergency first aid procedures are provided in the health hazards section. In case of overexposure, it is essential that these first aid procedures be carried out immediately.


The safe handling section explains the normal safe handling and storage procedures for the product. It also lists emergency procedures to be used in the event of a spill.

The safe handling section also details the appropriate method for disposing of the product.


The control measures section describes the clothing, equipment, and accessories that should be worn for personal protection when the product is handled.

This section also details any industrial hygiene practices that should be followed when you are working with the product, and it states whether special equipment such as eyewash stations or decontamination showers should be available.

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