HAZWOPER 40 Lesson 5: Hazardous Chemical Awareness

DOT Classifications

1.1 - Explosives with a mass explosion hazard 1.2 - Explosives with a projection hazard 1.3 - Explosives with predominantly a fire hazard 1.4 - Explosives with no significant blast hazard 1.5 - Very insensitive explosives 1.6 - Extremely insensitive explosive articles Forbidden explosives are not allowed to be shipped by common carrier. One additional classification used by DOT is for blasting agents, which are a mixture of oxidizers plus fuels and are insensitive to heat and shock.

If a liquid has a pH of ______, its H+ ion concentration is very low. 1 11 15

11

Liquid Hazards

Liquid hazards must be handled carefully to avoid splashing. Skin damage can be caused by contact with a liquid corrosive.

The Hazard Communication Standard (HCS)

One of the needs addressed by the OSH Act is the protection of workers from chemicals in the workplace. In response to this need, OSHA issued the Hazard Communication Standard (29 1910.1200 CFR) in 1983 and expanded it to cover all workers in 1987. The Hazard Communication Standard (HCS) necessitates employers to evaluate chemical hazards in their facilities and to communicate the hazard information to employees. A hazard communication program must include the following steps: Perform a chemical inventory. Obtain and file a material safety data sheet (MSDS) for each chemical, and label all containers and storage areas containing chemicals. Train employees about the hazards and proper use of the chemicals. Make the HCP available in writing.

Lesson Focus This lesson focuses on the following topics:

Part 1: Methods of Hazard Identification The Hazard Communication Standard (HCS) Labeling Chemical Names with Potential Hazards Part 2: Hazardous Characteristics and Protective Measures Corrosive Health Hazards Protective Measures Hazardous Mixtures Part 3: Solvents and Oxidizers Solvents Solvent Hazards Oxidizers Unstable Materials

Basic Rules of Handling Flammable Materials (Video)

https://player.360training.com/ICPFileSystem/PersistentAssets/413757/645018/HAZ40-L5-V1-GM_v2.mp4

The Safety Data Sheet (SDS) A safety data sheet is a written document containing specific information on defined hazardous chemicals and their potential effects. The United Nations Global Harmonization Standard (GHS) requires the following 16 sections:

1. Identification 2. Hazard(s) Identification 3. Composition/Information on Ingredients 4. First-Aid Measures 5. Fire-Fighting Measures 6. Accidental Release Measures 7. Handling and Storage 8. Exposure Controls/Personal Protection 9. Physical and Chemical Properties 10. Stability and Reactivity 11. Toxicological Information 12. Ecological Information 13. Disposal Considerations 14. Transport Information 15. Regulatory Information 16. Other Information In addition to a MSDS, the HCS requires that every container of hazardous materials be labeled by the manufacturer. For example, the Department of Transportation (DOT) places placards on bulk packages alerting handlers of the package's contents. Labels must provide the chemical identity of the hazardous material, any hazard warnings, and the name and address of the manufacturer. This data helps employees identify what chemicals they are handling and what precautions to take to ensure the safety of themselves and others in the workplace.

Solvents Flammable Solvents

A flammable liquid refers to any liquid having a flashpoint below 100 degrees oF. (37.8 deg. oC.), except any mixture having components with flashpoints of 100 degrees oF. (37.8 deg. oC.) or higher, the total of which make up 99 percent or more of the total volume of the mixture. Note: The DOT and EPA define flammable liquid as a liquid with a flash point of less than 140oF. Flammable solvents have also been in use for many years. The physical hazards that they bring to the workplace are in the form of fire and explosion. Acetone, ether, hexane, ethanol, toluene, and xylene are common flammable solvents. With flammable solvents, fire protection is of primary concern. The proper use of safety cans, grounding and bonding, and flammable storage cabinets is critical

Corrosives and Ignitable Materials

A subsequent and more probable contact is that of a corrosive with a flammable or combustible material. There are many possible reactions, with the exact type dependent upon the specific corrosive and flammable/combustible material. Examples of the hazards that could be encountered are when a strong acid or base is mixed with a polar, or water soluble flammable or combustible liquid, heat will be generated in a manner similar to that seen when water is added to an acid. Because of the increase in temperature, there will also be an increase in the amount of vapor that is generated by the liquid. This means that the liquid, normally at the temperature of its environment, will be warmer than its environment. For instance, a liquid that is normally considered to be below its flash point (the temperature at which enough vapor is produced for a flash ignition to occur) may have been heated to a temperature above its flashpoint. This means that if enough vapor is present and an ignition source is found, a fire will result.

Explosive Trains

An explosive device can come in a variety of shapes or forms. It may be a liquid in a glass container, black powder in a pipe, a gel, a plastic, a rolled up detonating cord, etc. Generally speaking, an explosive is any device that contains fuel, an oxidizer, and a detonating device. This chain of events is called an explosive train. Although the chain of events in an explosion can be very complex and can include a number of variables (factors), some of the basic components of an explosive train are: A primer An igniter A detonator A booster charge A main charge A safety fuse attached to a blasting cap, which in turn is attached to a high explosive, becomes an explosive train. The safety fuse is a textile cord which acts as an igniter. Wrapped around the textile cord is black powder, which primes the blasting cap at the other end. The blasting cap, in turn, detonates the main charge or the high explosive. Sometimes a booster charge is used with a high explosive that is difficult to detonate. The booster is also a high explosive, but is much more sensitive than the main charge.

Oxidizers

An oxidizer is any material that will gain electrons during a chemical reaction, which stimulates the combustion of organic materials. The primary hazards associated with oxidizing compounds are similar to those of the oxidizing elements. They include: Intensification of combustion Spontaneous ignition Explosion Toxic fume production

Hazardous Mixtures

Another potential hazard is the mixing of different types of materials at any waste site. This is particularly true with corrosives, simply because there are so many around in so many locations. They are used in everything from flashlight and car batteries, to toilet bowl cleaners, disinfectants, rust-proofing agents, and in metal ore processing and petrochemical refining. Let's take a look at some of the possible complications that could develop if corrosives were to mix with various types of materials.

Unstable Materials

Any substances that will spontaneously decompose, polymerize, or self-react under conditions of shock, temperature, or pressure are called unstable materials. A reactive hazardous material needs an outside stimulus to get it to react, but an unstable hazardous material does not need an outside stimulus. Treat unstable materials as explosives until they are proven otherwise. Do not move or handle a material until its stability can be verified

Learning Objectives

At the completion of this lesson, you will be able to: Summarize and follow the Hazard Communication Standard. Evaluate chemical hazards in your facilities and communicate hazard information to employees. List the information that labels are required to have and correctly label hazardous chemicals. State and verify chemical names and word fragments and the hazards associated with them. Define, describe, and give examples of corrosive materials and corrosive health hazards. Safely handle and deal with corrosive or caustic material spills. Take preventative/protective measures to minimize occurrences of corrosive materials exposure. Identify, detect, and safely handle hazardous mixtures and solvents. Treat solvent exposure and aid others in cases of solvent spills or releases. Examine the effects of various common extinguishing agents in fighting oxidizer fires. Identify and safely handle, control, and stabilize unstable materials.

Two main types of materials powerful enough to corrode steel are: Acids or corrosives Bases or caustics Acids or pH Both A & B

Both A & B

Corrosive Health Hazards

Corrosive class chemicals, of which sulfuric acid is the most common example, are the second-most often used, transported group of hazardous materials. Only flammable liquids are more common. Corrosives are used in everything from batteries to disinfectants so it is important to be able to recognize corrosive class chemicals. A corrosive material is any liquid that has a severe corrosion rate on steel. Because a corrosive material can destroy steel, it is possible for it to corrode many other substances, including human tissue. Two main types of materials are powerful enough to corrode steel (and therefore, human tissue). These two types of materials are: Acids or corrosives Bases or caustics Fast Facts: https://player.360training.com/ICPFileSystem/PersistentAssets/412923/642865/HZ_L5_Corrosives.jpg The term pH is often used when discussing acids or bases. It is often said that "the liquid has a low pH". What is pH? By definition, "pH is the negative log of the concentration of H+ in solution." As the concentration of H+ increases, the pH number decreases. If a liquid has a pH of 11, its H+ ion concentration is, very low. Bases have very low H+ concentrations and rather high OH- concentrations. So, we say that a liquid with a pH of 11 is a base. The pH can range from 0 to 14, with the acids on the low end (0 to 7), and the bases at the high end (7 to 14). Solutions with a pH of 7 are neutral.

Do's and Dont's for Solvents

DO use only approved and labeled containers for storing and transporting solvents. DO make sure there is proper ventilation when using solvents. DO keep flammables away from heat and ignition sources. DO check that containers and hoses are in good working condition. DO ground/bond yourself and your work to avoid any transfer of static charge. DON'T mix solvents - unless instructed to; follow instructions exactly and double check. DON'T smoke, eat, or drink around hazardous substances. DON'T wear contact lenses around toxic vapors. DON'T track hazardous materials from one location to the next.

Solid Hazards

Dusts from solid corrosives can produce severe internal or external injuries. Massive exposures to a strong corrosive can be fatal within a matter of minutes.

The following is a list of some examples of potentially hazardous elements:

Element that Signal Potential Hazard Aluminum Antimony Arsenic Barium Beryllium Bromine Cadmium Chlorine Chromium Cobalt Copper Fluorine Hafnium Indium Iodine Lead Manganese Mercury Molybdenum Nickel Platinum Rhodium Selenium Silicon Silver Tellurium Thallium Tin Tungsten Uranium Yttrium Zirconium Besides the names of some elements, the presence of certain words and word fragments in the names of chemicals can show possible hazards. Not every chemical compound whose name contains these words or word fragments is hazardous, but most are. Chemical names that end in the following suffixes may also signal a hazard: -ite -ate -ide

Control and Stabilization

Even though water is a primary tool used in many emergency situations, workers must refrain from using it on water-reactive materials that have spilled, leaked, or ignited. Many metal fires cannot be put out with water or by other means, for that matter. The important point is that workers must attempt to avoid committing themselves to actions that make a situation worse instead of better. When there are large fires involving water reactives, it is best in most situations to reduce human exposures and let a fire burn Treat unstable materials as explosives until they are proven otherwise. Do NOT move or handle a material until its stability can be verified. Be advised that if you stumble across jars with chemicals, hermetically sealed 55-gallon drums, or cargo carriers with hazardous materials that must be inhibited, you should begin to step lightly. Such materials may be unstable. Some materials such as Picric Acid can have unstable salts that are shock sensitive around the lid of the container from moisture intrusion. Simply tapping on the container or using tools to open it can be extremely dangerous.

Explosives

Explosives are chemical compounds or mixtures of various compounds that are capable of undergoing rapid transformations with the simultaneous production of large quantities of heat and gases. This release of high heat in the presence of gases causes the gases to expand rapidly. Their rapid expansion exerts an exceedingly high pressure on the surrounding environment. The pressure exerted by such explosives causes shock waves to travel at velocities that can exceed the speed of sound.

Corrosives and Poisons

First, if corrosives come in contact with poisons, such as cyanide or sulfide salts, the primary concern is the possible toxic vapors that could be produced by the decomposition of the poison. The vapors could be more toxic than any of the corrosive vapors themselves.

Halogenated Solvents

Halogenated solvents are hydrocarbon solvents that consist of one or more halogen atoms (Cl, F, or Br) attached to the hydrocarbon molecule. Halogenated solvents, sometimes called safety solvents, have been in wide use in the last twenty years. They do not flash or burn, they have few acute health hazards and their cost has been reasonable. Today their safety is being questioned. Flammability is not a problem with halogenated solvents, but in a fire the byproducts of decomposing halogenated solvents are deadly. Halogenated solvents have been shown to cause chronic health problems because of inhalation and skin contact; they have also been shown to have an adverse effect on the environment. Many play a roll in the depletion of the ozone layer and are listed as greenhouse gases. General halogenated solvents are the Freon-based solvents, methylene chloride, trichloroethylene, and 1,1,1-trichloroethane.

Treatment for Solvent Exposure If you should encounter an unconscious person near a solvent spill or release:

Immediately call for help. Move the victim to fresh air and give CPR if necessary. Do not attempt to rescue if there is any reason to believe that the cause is solvent vapor without wearing proper protective equipment. Have a standby observer present. Make sure the victim gets medical help. Don't become part of the problem. Never attempt rescue in an confined space unless properly trained, equipped, assisted, and otherwise prepared otherwise you can become part of the problem.

Introduction

In our everyday lives, we encounter and use hazardous chemicals. We use bleach to clean the floors and fertilizer for our yards. Because these materials seem commonplace, often people become lax and careless around them. This happens in the workplace as well, and the outcomes can be more dangerous when dealing with large quantities of chemicals. A basic knowledge of chemical hazard classes, chemical terms, and basic chemical hazard awareness is critical in the safety of workers.

Extinguishing Agents for Oxidizers

It is important to examine the effects of various common extinguishing agents in fighting oxidizer fires because of the way oxidizers behave when involved in fire. The best extinguishing agent is water. There are, however, hazards involved in using water, including: Impregnation of combustibles Run-off Possible water reactivity of the oxidizer

Protective Measures

It is safer to handle corrosive material if preventative measures are taken first to minimize the occurrences of exposure. The most common tissues exposed to corrosive material can be protected by wearing protective equipment. Hands can be protected by gloves, and goggles can protect the eyes. In some instances, it may be necessary to wear a face shield or work behind a splash shield in addition to standard protection. It is always necessary that any personnel working with acids and bases not wear contact lenses. In the event of exposure, contact lenses can become "welded" to the eye, leading to blindness.

Labeling

Labeling and placarding is often considered as the quickest source of information. The HCS requires every container of hazardous materials (with a few exceptions) to be labeled by the manufacturer. A label can contain more information, but it must contain: Chemical identity and/or trade name of the hazardous material. Hazard warning(s). Name and address of the chemical manufacturer

Flammables

Many flammable liquid vapors are toxic below their detection limit. Explosive gas meters detect flammable liquids, but meters are not equally sensitive to all gases, thus, any indication of flammable gas should be of concern. Note also that flammable ranges are in percentages; one percent is equal to 10,000 parts per million. An explosive gas meter cannot be used to detect gases at PEL levels because PEL concentrations are generally less than 1,000 ppm or 0.1 percent total atmosphere. Noteworthy: The resulting hazard of flammable solvents and the primary hazard of other solvents are the health effects.

Spontaneous Ignition

Many standard rules relating to combustion no longer apply in the presence of oxidizers. For example, a material that is normally difficult to ignite may flash into flames in an oxidizer enriched atmosphere. In this situation, the flammable range and flashpoints normally used to measure the potential "flammability" of a flammable liquid or material are greatly modified. The oxidizer widens a material's flammable range. For example, with four times as much as the oxygen present, the LEL may be as much as four times lower and the UEL as much as four times higher. Please note that an "oxidizer-enriched" atmosphere may contain oxygen, fluorine, chlorine, or other oxidizers to be introduced in upcoming paragraphs. It is important to know that oxidizers DO NOT BURN; rather they support and intensify combustion.

Chemical Names with Potential Hazards

Many times chemical names and terms can be very confusing and misleading. A single letter in the name of a chemical can mean the difference between a toxic to non-toxic compound. No spill response worker should ever assume that the hazards of a particular chemical are known without verifying the information. The name must be verified and the hazards must be verified. Verification can come from the label, safety data sheets, reference books, or from technical specialists. A chemist or other specialist should be available to assist in supervision of spill cleanup activities. If the hazards of a mixture cannot be confirmed, use maximum protective procedures. The name of a chemical is the first indication of its potential hazard. Even before the label or SDS is checked, the presence of certain elements in the chemical name suggests the probable existence of hazards.

Polychlorinated biphenyls (PCBs)

PCBs are a common term for the family of 209 chlorinated isomers of biphenyl. Polychlorinated biphenyls (PCBs), discovered in the late nineteenth century, were introduced into the United States industry on a large scale in 1929 and have been in use since that time in most industrial nations. PCBs have chemical stability, resistance to heat, low flammability, and high dielectric constancy. The PCB mixture is a colorless, viscous fluid, is relatively insoluble in water, and can withstand high temperatures without degradation. These characteristics are precisely the qualities that make PCBs non-biodegradable The higher-chlorinated isomers are not readily degraded. PCBs are transported through the biosphere in water and are attracted to sediments. These phenomena are the result of bio-accumulation and bio-magnification in the food web. Uptake of PCBs by plants has also been reported, but it is generally small and does not directly contribute to substantial human contamination. In a few instances, poultry, cattle, and hogs have been found to contain high concentrations of PCBs after the animals have eaten feed contaminated with PCBs. PCBs have been detected in human fatty (adipose) tissues and in the milk of cows and humans The estimated percentage of the United States population with detectable levels of PCBs was nearly 100 percent in 1981. The estimated percentage of the United States population with greater than 3 ppm PCBs in their tissue was 2.7 percent, in 1972, and less than 1 percent in 1981. PCBs can enter the body through the lungs, gastrointestinal tract, and skin, circulate throughout the body, and be stored in fatty (adipose) tissue. Except for occupational contact, human exposure is mainly through food. PCBs can cause chloracne, skin discoloration, liver dysfunction, reproductive effects, developmental toxicity, and oncogenicity in exposed humans.

Which of the following statement is FALSE? If a caustic is spilled, it will be neutralized with an acid. Acids dissociate to produce hydrogen ions (H+). Bases dissociate to produce hydroxide ions (OH-). Percent and polarity are expressions that identify concentration.

Percent and polarity are expressions that identify concentration.

Placarding

Placarding is a system of hazard warning required by the Department of Transportation (DOT). Placards are placed on bulk packages, such as portable tanks, and on transportation vehicles carrying hazardous materials during transit. DOT labels are more or less identical to DOT placards. However, labels are smaller in size and are required on non-bulk packages, such as boxes and canisters. Many employers find DOT labels to be convenient for marking hazardous materials within their facilities.

Primary and Secondary Explosives

Primary high explosives are extremely sensitive to heat and shock while secondary high explosives are much more stable. Thus, a small amount of primary high explosive is used to detonate a much larger amount of secondary high explosive in some explosive devices. A primary system for classifying explosives is the one employed by the Department of Transportation (DOT).

When there is a large fire involving water ______, it is best in most situations to reduce human exposures and let the fire burn. Corrosives Caustics Reactives Flammables

Reactives

The National Fire Protection Association (NFPA 704) signing system

The National Fire Protection Association (NFPA 704) signing system is designed to provide information on possible chemical risks to emergency responders. NFPA signs rate a chemical's hazard in three areas: health, flammability, and reactivity. A fourth (white) area of the sign indicates any special hazard. Local fire codes generally require facilities to post NFPA signs on buildings and doors to warn that hazardous chemicals are within. In addition to package labels containing information required by OSHA and GHS (see above), many employers add small adhesive labels using the NFPA design. These provide an additional means of warning employees of hazards. "Noteworthy" It is important to remember that the Hazard Communication Standard applies to hazardous chemicals that are being used in a facility, not to hazardous waste. Therefore, waste site workers use labels, placards, and signs as a source of information, not identification. https://www.osha.gov/Publications/HazComm_QuickCard_Pictogram.html

Treatment for Exposure

The best way to stop the chemical action of corrosives is flushing, done to flush out and neutralize the material. After flushing is complete, the victim should be treated with standard first aid practices. It is important to keep in mind that the extent of injury is dependent on the concentration of the acid or base, the quantity, body area affected, and the duration of contact.

Toxic Fume Production

The final primary hazard of oxidizers is the effect that inhalation of their vapors and smoke has on the respiratory system. Both vapors and smoke dissolve in the mucus lining of the respiratory tract and produce liquid (usually corrosive) that can damage the tissues of the respiratory tract.

Corrosives and Metal

The final type of contact to be considered is that of a corrosive with a metal. Simply by examining the definition, it becomes evident that one of the possible reactions is the destruction of the metal itself. This is of great importance when the particular metal happens to be the same metal that makes up the container in which the corrosive is stored. This might sound a little silly, but this type of problem has occurred in the past and is usually difficult to control. The other type of reaction that can occur simultaneously with metal destruction is the production of hydrogen gas. This can be especially dangerous when it occurs indoors simply because of the nature of the hydrogen that is produced. This is an example of why you should never charge car batteries indoors.

Intensification of Combustion

The hazard most likely to be encountered involving oxidizers is the oxidizer intensifying combustion. The rate of combustion increases as well as the heat of combustion. This is because there is more fuel being oxidized than under normal conditions. The oxygen produced by any of these oxidizing compounds is greatly dependent on the amount of heat to which it is exposed. The greater the heat exposure, the greater the rate of oxygen production. This in turn leads to a greater rate of combustion and additional heat production.

Solvent Hazards - Explosion or fire

The major hazard of flammable liquid solvents is the physical hazard of fire or explosion. Flammability refers to the ability of a material to generate a high concentration of flammable vapors in an unconfined area under normal circumstances. There are three factors necessary for a fire: Fuel (something to burn) An oxidizer to promote burning (oxygen source) An ignition source The flashpoint is the lowest temperature at which a liquid gives off enough vapor to form a flammable mixture with air. Flammable liquids (OSHA and NFPA definition) have a flashpoint below 100F. Class II combustible liquids are also hazardous; their flashpoints are between 100F and 140F. The DOT and EPA define flammable liquid as a liquid with a flash point of less than 140F. The ignition point is the temperature that the vapor must reach to ignite. There is an inverse relationship between flashpoint and ignition temperature. The higher the flashpoint the lower the ignition temperature. Gasoline has a low flashpoint (-40oF) and a high ignition temperature (about 850oF). Number 2 fuel oil has a high flashpoint (120oF) and a lower ignition temperature (about 650oF). The minimum concentration of flammable liquid vapor in air necessary for a mixture to ignite is called the Lower Explosive Limit, or LEL. Anything below that limit is too low to ignite. The Upper xplosive limit, UEL, is the concentration of flammable liquid vapor in the air that is too rich to ignite. It will not burn because there is too little oxygen. The vapor has displaced the oxygen and the oxygen concentration has dropped to less than 14 percent. The flammable or explosive range includes everything between the upper and lower explosive limits. Whenever flammable liquids are spilled or whenever combustible liquids are spilled on hot surfaces, in a quantity that can reach the flammable range, management and emergency services should be notified. Generally, a spill of one or more gallons should bring this response. As with all generalities, specific conditions may call for assistance with even smaller spills. One example would be a spill of flammable liquid into a sump or pit. Far less than a gallon can create a fire hazard in a confined space. It is possible to detect the presence of hazardous flammable liquid vapors by their smell.

Vapor Hazards

The most dangerous type of hazard is a vapor hazard. "Fuming" liquids can spontaneously produce vapor. If a vapor cloud is generated, large-scale evacuation is usually required. Injuries from vapors include damage to the mucous membranes (eyes, throat, and airway) and irritation to the respiratory system. Vapor Pressure is a liquid property related to evaporation. At room temperature and sea level there is one atmosphere of pressure which pushes down on a liquid in a container. As the liquid is heated and it boils it has enough energy to overcome the pressure of the atmosphere and it escapes in gas form, or vapor. Materials containing a vapor pressure less than one will boil at room temperature and materials containing a vapor pressure greater than one will remain liquid at room temperature. A material's vapor pressure is a crucial consideration to take into account when responding to a materials release.

Hazards

The primary hazards associated with oxidizing compounds are similar to those of the oxidizing elements. They include the intensification of combustion, spontaneous ignition, explosion, and production of toxic fumes. Of these four hazards, spontaneous ignition is a causative hazard (causing the incident). Explosions, however, may be causative or subsequent, which means they follow the start of the incident.

pH

The term pH is often used when discussing acids or bases. It is often said that "the liquid has a low pH". What is pH? By definition, "pH is the negative log of the concentration of H+ in solution." As the concentration of H+ increases, the pH number decreases. If a liquid has a pH of 11, its H+ ion concentration is, very low. Bases have very low H+ concentrations and rather high OH- concentrations. So, we say that a liquid with a pH of 11 is a base. The pH can range from 0 to 14, with the acids on the low end (0 to 7), and the bases at the high end (7 to 14). Solutions with a pH of 7 are neutral.

Only flammable liquids are more commonly used and transported than corrosives. True False

True

Characteristics of Unstable Materials

Unstable hazardous materials exist as liquids or crystalline solids. Looking at the molecules (two or more atoms that are bonded together chemically) of unstable materials, it is found that many of these share electrons in order to form molecules or compounds. The sharing of electrons between atoms is called "covalent bonding." Forming or breaking a covalent bond is easy in some situations. Thus, many unstable materials have bonds that are easy to form and break; therefore, it doesn't take much to set them off and running. Two important types or groups of unstable materials are: Organic peroxides Monomers

Explosion

We all know what happens when oxygen is mixed with flammable materials such as solvents or gasoline. There is a high potential for serious fire or explosion. As the decomposition progresses, additional heat is generated, which further accelerates the decomposition rate. The same is true for peroxides. Pure peroxides are often explosive.

Corrosive Health Hazards

We discussed earlier that corrosives can destroy living tissue (referred to as chemical burns). Some acids and bases are so corrosive that even momentary exposure to the skin will produce severe damage.

Lesson Description

We encounter and use hazardous chemicals all the time in our everyday lives. Because these materials seem commonplace, often people become lax and careless around them. This happens around the workplace as well, and the outcomes can be more dangerous when dealing with large quantities of chemicals. A basic knowledge of chemical hazard classes, chemical terms, and basic chemical hazard awareness is critical in the safety of workers in the workplace. The Hazardous Chemical Awareness lesson covers chemicals and the hazards they present in the workplace to provide this basic knowledge and increase chemical hazard awareness. The lesson examines the Hazard Communication Standard (HCS) and lists the required steps for any HCS program. Other topics examined in the lesson include proper labeling of chemicals, verification of chemical names, corrosive materials and safety hazards, and unstable materials.

Acid-Base Neutralization

When dealing with corrosive or caustic spills the usual response is to neutralize the chemical through a neutralization reaction. For example, if an acid is spilled it will be neutralized with a base (caustic). Conversely, if a caustic is spilled it will be neutralized with an acid. The reaction between an acid and a base will include producing a large amount of heat, the splattering of liquid materials, and possibly the production of steam explosions, hydrogen gas, and toxic or irritating gases. In an acid-base neutralization reaction it is important to lessen the possibilities of an uncontrolled reaction and avoid the situations described above. To successfully do this, an understanding of the neutralization process is important. When mixing acids and bases, three general reaction products are formed in some state: Salt Water Heat The following chart shows a common neutralization reaction: Since energy, in the form of heat, is always produced in a neutralization reaction, controlling the amount of heat energy released is very important. Controlling this energy release will prevent the unwanted violent reaction that can place responders at risk. So, an understanding of the terms, strength and concentration, as they relate to acids and bases is essential. Image: https://player.360training.com/ICPFileSystem/PersistentAssets/412949/642908/HZ_L5_Corrosives3.jpg

Strength vs. Concentration

When most people speak of strong acids (or bases) they are actually referring to the concentration of the acidic or basic solution. These two concepts are often confused. Strength is defined as "the percentage of dissociation that occurs when an acid or base is mixed with water." All this means is how much the material (solid or liquid) molecules come apart (dissociate) in water to form electrically charged particles (positive or negative ions). Acids dissociate to produce hydrogen ions (H+) and bases to produce hydroxide ions (OH-). The greater the dissociation (increasing H+ or OH-), the greater the strength of the resulting acid or base solution. Image: https://player.360training.com/ICPFileSystem/PersistentAssets/412947/642903/HZ_L5_Corrosives2.jpg Concentration is defined as the "amount of material (acid or base) mixed with a certain amount of water expressed in terms of percentage by weight or volume." The more water by percentage the more dilute the resulting solution. Conversely, the less water added the more concentrated the resulting solution. If one has concentrated HCl, it means that the liquid material has the maximum amount of HCl dissolved in that particular amount of water. If we were to add any more HCl gas to the solution, no more would or could dissolve, but rather it would just bubble through the liquid and escape. Now, if we have a fifty percent (50 percent) concentration of HCl, we are saying that we have taken a given amount of the concentrated solution and mixed it with an equal amount of water. If we compare the number of H+ ions in the concentrated solution with the number of H+ ions in the 50 percent solution, we will find that the 50 percent solution has only one-half the number of H+ ions as are found in the concentrated solution. Percent and molarity are expressions that identify concentration. Remember, the larger the number before the term, the more concentrated the solution.

Static Electricity (Video)

https://player.360training.com/ICPFileSystem/PersistentAssets/413758/645021/HAZ40-L5-V2-GM_v2.mp4

Grounding and Bounding (Video)

https://player.360training.com/ICPFileSystem/PersistentAssets/413760/645022/HAZ40-L5-V3-GM_v2.mp4

Storing Flammables (Video)

https://player.360training.com/ICPFileSystem/PersistentAssets/413761/645025/HAZ40-L5-V4-GM_v2.mp4