Chemical reactions can be extremely hazardous if they are not thoroughly understood and controlled. When intentional or unintentional reactions get out of control, they can result in fires, explosions, or releases of toxic fumes or gases. You and your coworkers could be injured—or even killed—as a result of an uncontrolled chemical reaction. It’s essential, therefore, that you know how to safely manage reactive chemicals to prevent accidents.

Session Objectives

The main objective of this session is to explain the hazards of working with reactive chemicals and the precautions you need to take to keep safe on the job. By the time this session is over, you should be able to:

• Identify reactive chemical hazards;
• Understand the nature of chemical reactions;
• Detect and manage reactivity hazards; and
• Respond safely to reactive chemical emergencies.

What You Need to Know

During the session, we’ll discuss:

• What reactive chemicals are;
• How they can endanger health and safety;
• The potential for hazardous chemical reactions in the workplace;
• The company’s hazard management program;
• Necessary precautions on the job; and
• Emergency reporting and response.

What Is a Reactive Chemical?

Let’s begin by defining what we mean by the term reactive chemicals.

• Reactive chemicals can be in the form of solid materials, such as granules or powders, or they can be in the form of a liquid.
• These chemicals can react with air, water, or other chemicals. Reactions can sometimes be very violent.
• Reactive chemicals can also be sensitive to shock, heat, or friction, and exposure to any of these could result in a fire or explosion.
• Chemical by-products from reactive chemicals can be corrosive, poisonous, or flammable—which makes them even more dangerous.

Health Hazards

• Reactive chemicals can also be hazardous to your health. Many reactive chemicals are corrosive and can destroy tissue. For example, alkali metals, like sodium, lithium, and potassium, can react with body moisture to cause severe burns to skin, eyes, nose, and throat. One reactive chemical, white phosphorus, reacts with air to form phosphoric acid, which is severely corrosive.
• Reactive chemicals can also be poisonous—azides, for example, which are used in the manufacture of airbags.
• Metal peroxides and chlorates can be irritating to the eyes and respiratory tract. Hydrazines, which are oxidizers, can irritate the eyes, skin, and respiratory tract. These chemicals are also suspected of causing cancer and harming the reproductive organs.
• Some reactive chemicals, such as nitrates, can cause dizziness, vomiting, convulsions, and death.
• And in confined spaces, free chlorine can cause asphyxiation and death.
• The safety data sheet, or SDS, for each reactive chemical explains the specific health hazards you could face.

Do you consult the SDS before working with any reactive chemical?

Fire Hazards

Reactive chemicals can also be a serious fire hazard through:

• Friction, such as when they are being mixed or transferred;
• Absorption of moisture, which can cause some water reactive materials to heat up;
• Spontaneous chemical changes, which often generate heat and can result in spontaneous combustion;
• Retained heat from manufacturing or processing, which can cause more reactions to occur, generating more heat, and potentially starting a chain reaction that could become a fire; and
• Ignition and burning vigorously and persistently.

Think about the reactive chemicals in our workplace and how they might react and become fire hazards.

Factors That Create Reactivity Hazards

Factors that could create workplace reactivity hazards include:

• Intentionally mixing chemicals to form different substances;
• Manufacturing processes that involve mixing, heating, or other physical processing of chemicals;
• Storage and handling of hazardous substances in the workplace;
• Processes that involve burning fuels and combustion; and
• Processes that generate heat.

Factors That Create Reactivity Hazards (cont.)

You also have to take into account the presence of chemicals identified as:

• Spontaneously combustible;
• Peroxide forming;
• Water reactive;
• Oxidizers;
• Self-reactive; or
• Incompatible, which means they can react with one another if they come in contact.

Detecting Hazards

Now let’s talk about detecting hazards. The best source of hazard detection information is the SDS. But there are other methods you can use to help detect reactive chemical hazards as well.

• For example, you can use your eyes to look for signs of a reaction, such as ignition, smoke, fumes, or bubbles, when the chemical is exposed to air or water. If you see any of these signs of reactivity, immediately evacuate to a safe distance and notify emergency personnel. We’ll talk more about emergency procedures in a few minutes.
• You can also use your nose to detect unusual smells or odors. Some oxidizers, for example, have odors that can be detected. But you shouldn’t rely exclusively on your sense of smell because it may be deadened even by small amounts of some gases.
• Another way to detect reactive chemical hazards is by using air-monitoring equipment to detect leaks and other problems that could release chemical gases into the air.

Do you routinely check the SDSs for reactive chemicals to locate information about hazard detection? You should.

Intentional Reactions

Let’s look more closely at some of the factors we’ve just discussed, beginning with intentional reactions. This means processing substances purposely so that a chemical reaction takes place.

• Intentional reactions may involve exothermic or endothermic reactions. Exothermic reactions release heat. Endothermic reactions absorb heat from the surrounding area or a heating source.
• Generation of heat is an important issue to consider. For example, will a mixture get hot when ingredients are combined or if cooling is lost? Too much heat can be hazardous.
• Adding heat can also be hazardous. Substances or mixtures that were not apparently reactive at one temperature can become dangerously reactive at a higher temperature.
• Many different hazard scenarios are possible with intentional reactions. All of them relate to losing control or containment of the intended reaction or starting another reaction, side reactions, or series of reactions that are not intended or expected.

Think about any processes that involve intentional chemical reactions.

Spontaneously Combustible Substances

• Spontaneously combustible substances react with the oxygen in the air, igniting and burning without any ignition source. For some spontaneously combustible substances, spontaneous heating is slow and could take minutes or hours. Pyrophoric substances, on the other hand, are spontaneously combustible materials that ignite instantly when exposed to air. They can also be water reactive.
• Spontaneously combustible materials must be identified as Department of Transportation, or DOT, Hazard Class 4.2 for shipping purposes and labeled SPONTANEOUSLY COMBUSTIBLE.
• On National Fire Protection Association (NFPA) diamond labels for spontaneously combustible substances, the red quadrant at the top of the diamond would have a rating of 4, indicating the highest severity of flammability hazard. NFPA labels also display numbers ranging from 0 for no hazard to 4 for extremely hazardous. Note that the GHS system works in the opposite way—GHS has hazard numbers ranging from 1 to 4, with 1 being the most hazardous and 4 being the least hazardous. Under GHS, there is no 0 (zero). Remember this to avoid confusion.
• Since exposure to air is very hazardous, you must always ensure that these substances are properly contained to prevent contact with air. Oxidizers (OX) promote combustion in other materials, causing a fire hazard.
• Examples of spontaneously combustible substances include aluminum alkyl, finely divided metals, and iron sulfide.

Do you work with any spontaneously combustible materials?

Peroxide Formers

• Peroxide formers are substances that will react with oxygen in air to form unstable peroxides that can explode.
• To prevent peroxide formation, these substances often have an inhibitor or stabilizer added.
• It’s important to note that peroxide formers may not be labeled as such. They are often identified by another hazardous characteristic, such as flammability.
• Peroxide formers should not be stored beyond their safe shelf life. Otherwise, the formation and concentration of unstable peroxides over time, followed by an event such as opening or agitating the container, could cause an explosion. Other possible accident scenarios include leaks or spills, opening containers and allowing air to get in, or insufficient inhibitors or stabilizers.
• Examples of peroxide-forming chemicals include 1,3-butadiene, 1,1-dichloroethylene, isopropyl ether, other ethers, and alkali metals.

Think about the peroxide formers used or stored in our workplace, the hazards they pose, and the precautions you need to take.

Water Reactives

• Water reactives are chemicals that react vigorously with water. The heat of this reaction can cause burns, ignite combustible materials, or initiate other chemical reactions. Flammable, corrosive, and toxic gases are often formed during the reaction. Even slow reactions can generate enough heat and gases to rupture a closed container.
• Water reactives may be identified as DOT Hazard Class 4.3 for shipping and labeled DANGEROUS WHEN WET. However, some water reactives may be classified and labeled as corrosives or poisons.
• In the NFPA label, the white quadrant at the bottom contains the “W” symbol. Just remember that even if the “W” isn’t present, the material might still be water reactive, just at a slower rate. Check the SDS.
• When handling or storing these reactives, avoid inadvertent contact with water. Even humidity in the air can cause a reaction if it comes in contact with a water reactive chemical.
• Examples of water reactive chemicals include sodium, titanium tetrachloride, boron triflouride, and acetic anhydride.

Do you work with any water-reactive chemicals on the job? Are you familiar with hazards and precautions?

Oxidizers

• Oxidizers are materials that readily yield oxygen or that easily react to promote or initiate fire. Most oxidizers can react with ordinary flammable and combustible liquids or solids. They can also react with many other substances.
• They may be identified as DOT Hazard Class 5.1, but they can also be classified as toxic or corrosive. Chlorine, for example, is labeled as DOT Hazard Class 2.3 and labeled POISON GAS. Liquid oxygen is Class 2.2 and labeled NONFLAMMABLE GAS and OXIDIZER.
• In the NFPA label, the white quadrant contains the “OX” symbol for materials that are oxidizers.
• When handling or storing oxidizers, avoid contact with any combustible or flammable materials.
• Examples of oxidizers include chlorine, hydrogen peroxide, nitric acid, nitrates, ozone, and hypochlorites.
• Under OSHA, GHS flame over circle pictogram corresponds to oxidizers. Think about the hazards and precautions associated with oxidizers used or stored in the workplace.

Self-Reactive Materials

Materials that self-react often do so with explosive force and speed. There are three forms of self-reaction:

• Polymerizing occurs when individual molecules combine to form larger molecules. Decomposing occurs when large molecules break apart into smaller, more stable molecules. And rearranging occurs when the atoms of molecules rearrange themselves into a different molecular structure.
• Substances that are DOT Hazard Class 1—explosives, or 5.2— organic peroxides, are likely to be self-reactive. However, some self-reactives are classified as flammable gases or liquids as well.
• In the NFPA label, the yellow quadrant on the right should have a rating between 1—the lowest hazard, and 4—the highest. Note that the GHS system works in the opposite way—GHS has hazard numbers ranging from 1 to 4, with 1 being the most hazardous and 4 being the least hazardous. Under GHS, there is no 0 (zero). Remember this to avoid confusion.
• For some highly self-reactive chemicals, such as shock-sensitive explosives and organic peroxides, mechanical shock, friction, sparks, or heat could be enough to start a decomposition reaction.

Think about the hazards and precautions associated with self-reactive chemicals used or stored in the workplace.

Incompatible Materials

There is also the risk of chemical reactions resulting from incompatible materials coming in contact with one another.

• The result of such contact could be an uncontrolled reaction that might include the release of toxic, corrosive or flammable gases; a fire or explosion; rupture of containers; the formation of shock sensitive or explosive chemicals; or heat generation that could cause other reactions.
• Potential scenarios in which incompatible chemicals could come in contact include situations such as a leaking liquid contacting an incompatible chemical stored nearby; materials pumped or transferred into the wrong process vessel; materials mislabeled or unlabeled; or the wrong material selected to add to a mixture or formulation.
• You should always consult a compatibility chart to make sure incompatible chemicals are stored and processed separately.
• Examples of incompatible materials include nitric acid and most chemicals, and ammonia and methacrylic acid.

Do you take precautions to keep incompatible chemicals separate?

Reactivity Hazards

Now it’s time to ask yourself if you understand the information that has been presented so far.

• Do you understand what a reactive chemical is?
• Do you understand the health and fire hazards?
• Do you understand factors that could cause chemical reactivity hazards in the workplace and the form those reactions could take?

It’s important to your health and safety that you understand all this information.

Now let’s go on to the next slide and talk about the company’s chemical management program.

Hazard Management Program

The company’s hazard management program strives to protect your safety and prevent incidents involving reactive chemicals.

• We actively monitor through walkaround inspections, informal spot checks, and specific discussions to ensure that chemical reactivity hazard management systems and procedures are actually being implemented and followed on a day-to-day basis.
• We also conduct periodic audits to examine procedures and practices. The goal is to make sure we comply with regulatory requirements, company standards and policies, and accepted industry practices.
• In addition, we work to manage change to ensure that all changes made in the facility that could introduce new reactivity hazards are identified, evaluated, and addressed to control risks.
• We also keep abreast of new technology so that we can benefit from the latest advances in process safety technology.
• And we take immediate corrective action whenever deficiencies, weaknesses, or vulnerabilities in our program are identified.

Are you familiar with the company’s hazard management program?

PPE

One of the best ways to manage chemical reactivity health hazards, of course, is to wear proper PPE to prevent exposures. The handling of many reactives requires special PPE. The SDS for a reactive chemical will tell you what type of PPE is necessary.

• Wear chemical-resistant gloves, since many reactive chemicals are poisonous, corrosive, or irritating to skin. Furthermore, when handling water reactive chemicals, moisture from your skin could cause a reaction, so you want to avoid skin contact for that reason, too.
• Wear splash goggles and a full-face shield to protect eyes from toxic, corrosive, or irritating chemicals.
• Chemical-resistant or fire-retardant clothing may also be required when handling certain reactive chemicals.
• Certain reactive chemicals might also require the use of an air-supplied respirator.

Think about the PPE you need when handling reactive chemicals.

Investigating Incidents

• Despite all our best efforts to detect and manage hazards, occasionally a chemical reactivity incident or near miss could occur. If this happens, report it right away.
• To manage chemical reactivity hazards effectively, we will investigate every incident or near miss so that we can determine what went wrong and how to fix it. Investigations identify root causes of hazardous conditions.
• They also point to previously unrecognized hazards and weaknesses in our safeguards and management system that can be corrected.
• And investigations identify the best measures to reduce or eliminate the underlying chemical reactivity hazard. Even when the hazard can’t be totally eliminated, we can still reduce the severity of potential consequences in the future if we understand the things that go wrong today.
• We document all the findings of our investigations and will share what we have learned with you so that together we can all take effective action to prevent future incidents.

Think about our incident reporting and investigation procedures. Are you ready to respond if you’re involved in an incident or near miss?

First Aid

In the event of an incident, you might also need to give first aid to coworkers or yourself if you are trained in first aid. Again, the best place to find specific information is the SDS for the reactive chemical you’re working with.

• Generally speaking, however, if you get a non-water reactive chemical on your skin, flush the area immediately with large quantities of cold water, and keep the affected area cold until you can get medical assistance.
• If you get non-water reactive chemicals in your eyes, go immediately to an eyewash station. Hold your eyelids open and flush with large quantities of water for 15 minutes. Then seek medical attention.
• If you think you might have inhaled chemical fumes or vapors, leave the area immediately and get to fresh air. Get medical attention.
• If you accidentally swallow a reactive chemical, seek medical attention immediately.

Do you know proper first-aid procedures for the reactive chemicals you work with? If not, check the SDSs soon so that you’ll be prepared.

Emergency Procedures

In an emergency involving reactive chemicals, the best thing to do is leave the area immediately if you’re not trained to handle the problem or if it’s clearly beyond your control.

• Immediately notify others of a reactive chemical spill or other emergency situation so that they, too, can evacuate the area.
• And be sure to notify your supervisor and the company’s emergency response team as well.
• Once safely out of the area, you can help by keeping others out.
• Stay away until the emergency response team tells you it’s safe to return.
• Remember, only specially trained and equipped personnel are authorized to clean up large spills of reactive chemicals. Some small leaks or drips can be absorbed with a rag or absorbent wipe, which can then be disposed of properly. But you should not attempt to clean up a larger problem unless you are authorized to do so.

Are you familiar with the company’s emergency response procedures so that you’d know exactly what to do in an incident involving reactive chemicals?

Emergency Equipment

The last item on our agenda today is emergency equipment. Make sure you know where to find—and how to use—emergency equipment such as:

• First-aid kits;
• Spill response supplies, if authorized;
• Safety showers;
• Eyewash stations; and
• Fire extinguishers, if authorized.

Do you know the location of emergency equipment in your work area?

It’s essential that you do so you can find it quickly in an emergency.

Hazard Management

• Do you understand all information that has been presented in the previous slides?
• Do you understand all the precautions we must take to effectively manage chemical reactivity risks and prevent accidents?

Make sure you know how to protect yourself and your coworkers from the hazards of reactive chemicals. Remember, these are potentially dangerous materials that can cause fires, explosions, and serious injuries and illness.

Now let’s go on to the next slide and wrap up the session with some key points to remember.

Key Points to Remember

Here are the main points to remember from this session on reactive chemicals:

• Reactive chemicals can be extremely hazardous and have to be handled with great care;
• Be able to identify different types of reactive chemicals in the workplace;
• PPE is critical to your health when working with reactive chemicals;
• Follow safe handling and storage procedures; and
• Follow emergency procedures.

This concludes the reactive chemicals training session.