Benzene is a highly flammable liquid solvent whose vapors can form explosive mixtures. Furthermore, exposure to benzene above certain limits is a health hazard.

Because of the serious hazards—both to safety and health—you must know how to work safely with benzene to prevent exposures, fires, and other accidents.

Today, we will discuss the physical hazards of benzene, health effects, the potential for exposure, air monitoring, medical surveillance, emergency response, and measures that can protect you from benzene exposure.

Session Objectives

The main objective of this session is to help you work safely with benzene. By the time the session is over, you should be able to:

• Identify benzene hazards;
• Understand exposure limits;
• Use engineering controls, safe work practices, and personal protective equipment, or PPE, to prevent exposures; and
• Know what to do in an emergency involving benzene.

Are you setting goals to help yourself remember the information after you complete the course?

Prequiz: How Much Do You Know?

Before we begin the session, let’s take a few minutes to see how much you already know about working safely with benzene. Decide which of the statements on the screen are true or false.

• Benzene can be hazardous in several ways.

– This is true.

• PPE is not effective protection against benzene hazards.

– This is false.

• Anyone who sees a benzene spill should clean it up.

– This is false.

• Long-term exposure to benzene can result in serious health problems.

– This is true.

How did you do? Did you get all the answers right?

If not, don’t worry. You’ll learn all about these issues and a lot more during the session. Are you prepared to concentrate on learning the training material?

Uses for Benzene

• Benzene is a solvent and an intermediate that is used to make other materials, such as polymers, plastics, fats, waxes, resins, oils, inks, paints, and rubber.
• It is also used in the manufacture of detergents, explosives, pharmaceuticals, and dyestuffs.
• Benzene is additionally found in trace amounts in gasoline and other fuels.

Think about how benzene is used in the workplace.

Potential Exposure

• Employees who work in industries that manufacture or use benzene may be exposed to the highest levels of benzene. Physical and mechanical processes, such as heating, pouring, spraying, open containers, and confined space exposures, are more likely to result in higher exposures.
• Benzene is also found in emissions from burning coal and oil, motor vehicle exhaust, and evaporation from gasoline service stations and in industrial solvents. These sources contribute to elevated levels of benzene in the air we breathe.
• Tobacco smoke contains benzene and accounts for nearly half the national exposure to benzene.
• You could also be exposed to benzene by consuming contaminated water. Benzene mixes very well with water.

Because of the potential for exposure on the job, OSHA requires employers of employees who may be exposed to train their workers about benzene safety, as we’re doing now, and explain the requirements of OSHA’s benzene standard.

Are you familiar with the requirements of the benzene standard?

Physical Characteristics

• Benzene is a colorless liquid with a sweet, pleasant odor. However, you don’t want to rely on the odor to warn you of the presence of benzene. By the time you detect and recognize the odor, you have already been exposed above safe levels.
• In addition to being a health hazard, benzene is volatile, which means it evaporates easily.
• What’s more, benzene vapors are almost three times heavier than air, which means benzene vapors will stay close to the ground and flow into low areas such as pits.
• And as we said at the beginning of the session, benzene is also highly flammable, and its vapors can form explosive mixtures. All of these physical properties make benzene a seriously hazardous substance.

You can find information about other physical properties of benzene in the safety data sheet—SDS. Be sure to read this section in the SDS carefully so that you will be familiar with all benzene’s properties.

Acute Health Effects

Acute, or short-term, health effects may occur immediately or shortly after exposure to benzene.

• In liquid or vapor form, benzene can irritate the eyes and skin.
• The upper respiratory tract, including the nose and throat, can be irritated by exposure to benzene liquids or vapors as well.
• Skin contact with liquid benzene or benzene vapors may result in redness and blisters.
• Benzene can cause symptoms of dizziness, light-headedness, headache, and vomiting.
• Finally, very high short-term exposures, on the other hand, can cause convulsions and coma, or sudden death from an irregular heartbeat.

Chronic Health Effects

Chronic, or long-term, health effects occur after exposure to benzene and can last for months or years.

• For example, long-term exposure to benzene can cause drying or scaling of the skin. While this may be uncomfortable, it’s minor compared to other potential long-term health effects.
• Repeated exposure to benzene affects the bone marrow, which produces blood cells. As a result, aplastic anemia, excessive bleeding, and damage to the immune system may occur.
• In addition, benzene is known to cause chromosomal changes in humans.
• There is also limited evidence that benzene affects the reproductive systems of animals and humans. Studies suggest that benzene may impair fertility in women exposed to high levels; however, these studies have been inconclusive.
• And, benzene is a known carcinogen in humans and has been shown to cause leukemia, which is cancer of the tissues that form white blood cells.

Fire Hazards

• As we’ve said, benzene is a flammable liquid. Benzene vapors can form explosive mixtures, and containers could explode in a fire. All ignition sources must be controlled when benzene is in use, handled, or stored.
• Poisonous gases may also be produced in a fire involving benzene.
• Since benzene vapor is heavier than air, vapors sink and can travel low to the ground for quite a distance to cause a fire or explosion far from the source. Vapors may travel to a source of ignition and flash back to the container, causing an even bigger, hotter, more dangerous fire.
• And, benzene also floats on water so that a fire can spread if water is used to extinguish the fire. That’s why you should use dry chemical, CO2 , or foam extinguishers to extinguish benzene fires.

Do you know what you’re supposed to do in the event of a benzene fire? Do you know where to find the right extinguisher to fight the benzene fire?

Permissible Exposure Limits

• OSHA’s permissible exposure limit—PEL—for benzene in the air is 1 part per million, or ppm, averaged over an 8-hour work shift. In addition, OSHA has set a short-term exposure limit—STEL—which requires that exposures may not exceed 5 ppm during any 15-minute work period.
• The American Conference of Government Industrial Hygienists— ACGIH—recommends an airborne exposure limit of 0.5 ppm averaged over an 8-hour work shift and 2.5 ppm as the STEL.
• The National Institute of Occupational Safety and Health— NIOSH— proposes a recommended exposure limit—REL—of 0.1 ppm averaged over a 10-hour work shift, and the STEL of 1 ppm.
• The exposure limits we’ve just identified are for air levels only. When skin contact also occurs, you may be overexposed even though air levels are less than the limits listed here. In addition, these limits are for healthy adults, not children, senior citizens or sick people.
• And, because benzene is a carcinogen in humans and because there may be no safe level of exposure to a carcinogen, all contact should be reduced to the lowest possible level.

Are you familiar with the other requirements of the benzene standard?

Exposure Monitoring

• To determine airborne levels of benzene in the workplace, we use special monitoring devices to monitor the air in areas where benzene vapors may be present. Employee exposure is determined from breathing zone air samples that are representative of each employee’s average exposure to airborne benzene.
• The 8-hour time-weighted average, or TWA, is determined from a sample representing the full shift of exposure.
• Short-term exposure levels are determined from 15-minute samples that are measured at operations where there is reason to believe exposures are high, such as when tanks are opened or filled, or when benzene is used in an uncontrolled situation during maintenance work.
• Measurement of breakdown products of benzene in the urine can also estimate personal exposure. However, the breath, blood, and urine tests must be done shortly after exposure and are not helpful for measuring low levels of benzene.

Are you familiar with our benzene exposure monitoring procedures?

Exposure Monitoring (cont.)

• If monitoring shows that employee exposure is at or above the action level of 0.5 ppm but below the TWA of 1 ppm, monitoring must be repeated annually. If monitoring shows employee exposure is above the TWA, monitoring must be repeated at least every 6 months.
• If periodic monitoring reveals that employee exposures are below the action level for at least two consecutive measurements taken at least 7 days apart, monitoring may be discontinued for that employee.
• Monitoring must be performed when there has been a change in production, process, control equipment, personnel, or work practices that may result in new or additional exposure to benzene. Monitoring must also be conducted whenever spills, leaks, or other breakdowns may lead to exposure and to ensure that the workplace has been returned to the level of exposure that existed before the incident.
• You will be notified of monitoring results within 15 days after the employer receives the results. You will be notified in writing either individually or by posting the results. If the PELs are exceeded, written notification will include corrective action being taken to reduce employee exposure to below the PEL.

Exercise

Now, it’s time for an exercise. On the screen you see a list of safety and health hazards. Your job is to select the ones that apply to benzene.

OK, now we’ll review the correct answers.

• Fire;
• Skin and respiratory irritation;
• Cancer;
• Explosion; and
• Blood cell damage.

How did you do? Did you get all the answers right? Would you do better on the next exercise if you went back and reviewed?

Review

Now it’s time to ask yourself if you understand all the information about benzene presented so far. For example, do you understand what we’ve said about:

• Uses for benzene?
• Potential exposure?
• Physical characteristics?
• Health effects?
• Fire hazards?
• Exposure limits?
• Exposure monitoring?

Understanding this information is important so that you can recognize benzene hazards and take proper precautions to prevent exposures.

Let’s continue now to the next slide and discuss what happens if benzene levels are above the PEL.

Exposure Above the PEL

• If employee exposure is at or above the PEL, engineering controls and work practices must be implemented to reduce and maintain exposure to benzene below the PEL.
• If engineering controls and work practices are not sufficient to reduce employee exposure below the PEL, they must be supplemented by the use of respiratory protection.
• If employee exposure is above the PEL, employers are also required to establish a written program with a plan to reduce employee exposure below the PEL. The written program must include a schedule of the development and implementation of engineering controls and work practice controls.

Engineering Controls

• Engineering controls are the most effective way of reducing exposure to benzene. Engineering controls are mechanical means that help reduce exposure to workplace hazards to safe levels, and are the preferred way to deal with benzene hazards whenever possible. According to OSHA, the best protection is to enclose or isolate benzene operations.
• In addition, OSHA requires the use of local exhaust ventilation at the site of benzene operations.
• Where possible, automatic pumps should be used to transfer liquid benzene from drums or other storage containers to process containers. This way you are not exposed to vapors coming from open containers.
• Finally, another effective engineering control is a vapor control system for containing the total vapors displaced during the loading of benzene-containing substances. Benzene-containing materials are displaced through a vapor processing or control system or transferred from the storage tank, as it fills, back to the tank truck, as it empties.

Think about the engineering controls we use to prevent benzene exposures.

Safe Work Practices

In addition to engineering controls, OSHA also requires the use of safe work practices to reduce hazardous exposures.

• For example, if your work clothing has been contaminated by benzene, you should change into clean clothing promptly. Do not take contaminated work clothes home. Family members could be exposed. Contaminated work clothes should only be laundered by individuals who have been informed of the hazards of exposure to benzene.
• If liquid benzene splashes in your eyes, go to an eyewash station and flush out the benzene immediately.
• If benzene gets on your skin, wash the area immediately. Do not let it sit on your skin because it can be absorbed into the fatty tissue.

Safe Work Practices (cont.)

• Immediately wash any areas of your body that may have come in contact with benzene whether or not known skin contact has occurred.
• Do not eat, smoke, or drink where benzene is handled, processed, or stored, since benzene can be swallowed and make you sick.
• After working with benzene, be sure to wash your hands carefully before eating, drinking, smoking, or using the toilet.
• Another important safe work practice applies to workers who enter confined spaces. Before entering a confined space where benzene may be present, check to make sure that the atmosphere in the space has been tested and that it is safe to enter.

Think about other safe work practices you use to prevent benzene exposures and accidents.

Handling and Storage

Here are some important handling and storage safety tips.

• Benzene should be handled, used, and stored only in regulated areas marked with warning signs.
• To avoid explosions when handling benzene, you need to understand that it is not compatible with oxidizing agents, such as perchlorates, peroxides, permanganate, chlorates, nitrates, chlorine, bromine and fluorine; fluorides; nitric acid; and diborane.
• You should always store benzene in tightly closed containers in a cool, well-ventilated area away from heat. Canisters and drums need to be electrically grounded whenever possible
• Sources of ignition, such as smoking and open flames, are prohibited where benzene is used, handled, or stored.
• Metal containers used in the transfer or pumping of benzene should be grounded and bonded before transfers are made.
• And, you should use only nonsparking tools and equipment in regulated areas, especially when opening and closing containers of benzene.

Hazard Communication

• Warning signs are posted at entrances to regulated areas where there is the potential for benzene exposure. You may see warning signs that say:

– Danger Benzene;

– Cancer Hazard;

– Flammable

—No Smoking;

– Authorized Personnel Only; or

– Respirator Required.

• Containers of benzene will also be labeled to warn you of hazards.

Warnings may include:

– Danger;

– Contains Benzene; and

– Cancer Hazard.

• You can also find information about benzene hazards in the SDS.

Respiratory Protection

• Respiratory protection must be worn when the concentration of airborne benzene is above the PEL. Generally, respiratory protection is necessary when engineering and work practice controls are not adequate to reduce benzene concentrations to safe levels or when these controls are not feasible, such as during maintenance or repair activities or during emergencies such as spills or leaks.
• We will select appropriate respirators for you to use in such circumstances. Depending on the situation and the risks, you will be required to use air-purifying or air-supplying respirators.
• We will train you to fit and use respirators properly.

Think about circumstances in which you might need to wear a respirator if you work in areas or situations in which benzene concentrations in the air may be above the PEL.

Other PPE

In addition to respiratory protection, other PPE may be necessary when engineering controls and safe work practices alone don’t eliminate the risk of benzene exposures. For example, you should always wear appropriate PPE to prevent skin and eye contact.

• To avoid skin contact with benzene, you should wear solvent-resistant gloves and protective clothing. Butyl Neoprene, polyvinyl alcohol, Silver Shield®, and Viton®/Neoprene are often recommended as protective materials for working with benzene.
• To protect eyes, wear impact- and splash-resistant goggles when working with liquid benzene.
• Wearing a face shield over goggles is also recommended with substances such as benzene.

Think about the PPE you might need to use to protect against benzene hazards.

First Aid

First aid for benzene exposure includes the following general procedures. Be sure to read the SDS for complete and specific first-aid information.

• If benzene gets in your eyes, immediately flush with large amounts of water for at least 15 minutes, occasionally lifting upper and lower lids. If irritation continues or vision appears to be affected, see a doctor as soon as possible.
• If benzene gets on your skin, quickly remove contaminated clothing. Immediately wash area with large amounts of soap and water. Seek medical attention. Make sure contaminated clothing is properly and safely washed before you wear it again.
• If you inhale benzene, get into fresh air immediately. If a coworker is overcome, get the person into fresh air. Begin rescue breathing if a coworker’s breathing has stopped and administer CPR if there is no pulse. Call for emergency assistance so that the victim can be promptly transferred to a medical facility.
• If you or a coworker swallows benzene, do not induce vomiting. Call for emergency medical assistance immediately.

Spills

• Only properly trained and equipped employees are allowed to clean up spills. If you’re not authorized to deal with a spill, report the spill immediately, and evacuate the area until cleanup is complete.
• If it is safe to do so, remove ignition sources as you leave the area.
• Those who are trained and equipped to deal with benzene spills will move in and cover the spill with an activated charcoal adsorbent, and then place cleanup materials in covered containers for appropriate disposal.
• They will also ventilate and wash the area after cleanup is complete.

Do you know exactly what to do in the event of a benzene spill?

Medical Surveillance

Employees who work with or are potentially exposed to benzene must be included in a medical surveillance program. All medical exams and procedures will be performed by or under the supervision of a licensed physician. All exams and procedures are provided without cost to employees.

• Before beginning employment in a job that could involve benzene exposure, you will be given a medical exam to determine a baseline assessment. This initial examination will include a detailed occupational history, complete physical exam, laboratory tests, and a pulmonary function test if employees are required to wear respirators.
• You will also undergo periodic, or annual, medical exams after that. These exams will include a brief medical history regarding any health changes, a complete blood count, a pulmonary function test, and any other appropriate tests as determined by the physician.
• If you are exposed to benzene in an emergency situation, you will be required to provide a urine sample for a urinary phenol test, which must be performed within 72 hours of exposure. If the result is greater than 75 milligrams phenol per liter of urine, you will need to undergo complete blood count testing for the following 3 months.

Medical Surveillance (cont.)

• A major component of the medical exam is a complete blood count, since benzene exposure impacts the blood. A complete blood count includes an erythrocyte count, leukocyte count, and thrombocyte count. If there is an abnormality in the blood counts, you will be referred to a hematologist.
• Medical exams will also evaluate the history of past and present symptoms of exposure to benzene. If you develop signs and symptoms commonly associated with toxic exposure to benzene, you will be provided with additional medical examinations.
• Within 15 days after the exam, you will be provided with a copy of the physician’s written opinion, which will contain information such as results of tests, medical conditions, recommended limitations, and so forth.

Are you familiar with our medical surveillance program?

Exercise

Now it’s time for an exercise. Choose the correct answer, a or b, to the questions on the screen.

• Which PPE is most appropriate for benzene?

– The correct answer is a—Goggles and respirator.

• Which is an example of an engineering control to prevent benzene exposure?

– The correct answer is b—Enclosed process.

• Besides engineering controls and PPE, what else is required to protect against benzene hazards?

– The correct answer is a—safe work practices.

• What is the best source of information about benzene hazards and protections?

– The correct answer is b—the SDS.

How did you do? Did you get all the answers right?

Review

Let’s take a few minutes now to review and make sure you understand the information presented in the previous slides. For example, do you understand what we’ve said about:

• Exposure above the PEL?
• Engineering controls and safe work practices?
• Handling and storage?
• Hazard communication?
• PPE and respiratory protection?
• Spills?
• Medical surveillance?

Understanding this information is important so that you can recognize benzene hazards and take proper precautions to prevent exposures.

Now let’s continue to the last slide and some key points to remember about this session.

Key Points To Remember

Here are the main points to remember from this session:

• Benzene is a hazardous substance that can affect your health and cause fires and explosions.
• You need to understand how benzene can be hazardous and how to prevent accidents.
• You should also understand exposure limits and monitoring procedures.
• You must know what to do in the event of an exposure or spill involving benzene.

This concludes the Working Safely with Benzene training session. Do you understand all the key points of the training material? Will you remember the information you learned in this course, or do you need to go back and review?