HAZARD COMMUNICATION

TRAINEE OBJECTIVES

After completing Section 8, you will be able to:

1. Define the following terms or words:
   
   

   Administrative controls	Substitution
   Engineering controls	Time weighted average

   
   
2. Identify the following acronyms:
   
   

   ACGIH	NFPA
   DOT	TWA
   MSDS

   
   
3. List the requirements of the Hazard Communication Standard's written program.
   
   
4. List the basic information that must be covered in the employer's training program for hazard communication.
   
   
5. List the information an employer must provide each employee.
   
   
6. List the exposure control measures that protect workers from exposure.
   
   
7. Demonstrate how to use MSDSs by completing an assignment sheet.
   
   
8. List the information that must be given on a typical label.
   
   
9. List the three basic types of labeling systems.
   
   
10. Demonstrate how to read a label by completing an assignment sheet.
    
    
11. Calculate TWA and determine exposure levels.

HAZARD COMMUNICATION STANDARD

An effective Hazard Communication Program needs the cooperation of employers and workers. The employer must provide workers with specific information and

training about hazardous chemicals in the work area. Workers must use the information and training to recognize chemical hazards in the work area and take steps to prevent exposure.

The Occupational Safety and Health Administration (OSHA) has implemented the Hazard Communication Standard for both the construction industry (29 CFR 1926.59) and general industry (29 CFR 1910.1200). The standard states:

"The purpose of this section is to insure that the hazards of all chemicals produced or imported are evaluated and that information concerning their hazards is transmitted to employers and employees."

These standards require that hazardous chemical manufacturers inform employers about a product's hazards. The employer must inform all workers who will use or come into contact with the chemical about its hazards.

Scope

The Hazard Communication Standard applies to any chemical known to be present in the workplace to which workers may be exposed during normal use. It also applies when exposure to chemicals may occur during a foreseeable emergency. On a hazardous waste site, the standard only applies to the hazardous materials or substances used for the clean-up process. The standard does not apply to:

• Hazardous waste
• Tobacco or tobacco products
• Wood or wood products
• Articles (chairs, tables, etc.)
• Food, drugs, and cosmetics
• Alcoholic beverages
• Consumer products

Workers must be trained in the standard because of the hazardous materials they use for cleanup. In order to use the standard correctly, one must know the difference between hazardous substances and hazardous waste.

Hazardous substances or materials are any substances or materials which in normal use can be damaging to the health and well-being of workers and the environment. Examples of normal use include processing plant work, manufacturing, and chemical decontamination on hazardous waste sites. Hazardous substances or materials cover a broad range of types, such as toxic, corrosive, and flammable.

Hazardous waste is a hazardous substance that has been discarded or otherwise designated as a waste material. It contains the same potential for damaging the health and well-being of workers and the environment.

Hazard Determination

The Hazard Communication Standard requires chemical manufacturers, importers, and employers to determine if the chemicals or substances they produce, import, or use in the workplace are hazardous. In most cases, hazard determinations are done by chemical manufacturers before the chemicals are sold to customers.

Written Hazard Communication Program

Under the standard, employers and/or contractors must develop, implement, and maintain a written Hazard Communication Program. This written program must be available at the workplace and provide the following information:

List the hazardous chemicals on the job site.

• Explain how the employer will inform workers of the hazards associated with nonroutine tasks involving hazardous chemicals.
  
  
• Explain labels and other forms of warning used by the employer.
  
  
• Explain how workers will be provided with material safety data sheets (MSDSs).
  
  
• Describe the training the employer will use to teach workers about hazardous chemicals.

Multiple Employer Sites

Many lead abatement job sites have more than one employer working on the site at the same time. The standard requires that all employers on a multiple employer site provide information to each other on the hazardous chemicals they are using. This sharing of information will help prevent worker exposure to chemical hazards from another employer. The written Hazard Communication Program of a multiple employer site must:

• Explain how MSDSs will be provided to the other employer(s), or identify the location of the MSDSs for each hazardous chemical the other employer's workers may be exposed to while working.
  
  
• List the methods an employer will use to inform other employer(s) of measures that need to be taken to protect workers during normal operating conditions and in foreseeable emergencies.
  
  
• Explain how the employer will inform the other employer(s) of the hazardous chemical labeling system being used.

The written Hazard Communication Program must be made available upon request to workers, their representatives, and OSHA.

Information and Training

The Hazard Communication Standard requires employers to provide specific information and training on hazardous chemicals so workers will:

• Be aware of the hazardous chemicals used on the job
  
• Know how to recognize these hazardous chemicals
  
• Know the safety issues and health effects of the hazardous chemicals
  
• Be able to protect themselves

As a minimum, training must cover the following hazard communication information:

• Requirements of the Hazard Communication Standard.
  
  
• Operations in the work area where hazardous chemicals are present.
  
  
• Location and availability of the:
  
  • Written Hazard Communication Program
  • List of hazardous chemicals
  • MSDSs for all hazardous chemicals used on site

Employers must provide or ensure that workers have been provided with the following information:

• The ways to detect the presence or release of hazardous chemicals in the work area. A chemical's characteristics are important pieces of information for workers. These characteristics include color, chemical state (solid, liquid, gas), and odor.
  
  
• The physical and health hazards caused by exposure to the hazardous chemicals on the job.
  
  
• How to protect themselves through work practices, personal protective equipment (PPE), and emergency procedures.
  
  
• Details of the Hazard Communication Program used by the employer, including labels, lists, MSDSs, and how workers can get and use hazard information.

Note: This section covers the general information that must be included in the Hazard Communication Program. The section does not fulfill an employer's obligation to supply workers with hazard communication training on site-specific hazards.

EXPOSURE GUIDES

When working around hazardous chemicals, exposure is an important consideration. Hazardous chemicals can have devastating health effects on the human body. Therefore, exposure guides are used to inform workers about warnings and exposure limits and to make decisions about worker exposure to chemicals.

Some exposure guides are general. They give instructions or information about a chemical using a short phrase, word, numbers, or symbols. For example, "avoid skin contact" and "avoid breathing vapors" are general exposure guides. These general guides are usually found on labels or placards on chemical containers. However, the chemical's identity needs to be known in order for general guidelines to be useful.

When the the employer knows both the identity of a chemical and its air concentration at the work site, more specific exposure guides can be applied. Permissible exposure limits (PELs) and threshold limit values (TLVs) are two commonly used exposure guides that deal with concentration levels.

Exposure limits set the basis for safe working exposures. In most cases, exposure limits refer to concentrations of a toxic substance in the air over a normal 8-hour work shift. Safe exposure limits represent conditions under which nearly all workers can be repeatedly exposed day after day without adverse acute or chronic health effects.

A product's MSDS must list chemical exposure limits. The limits may also appear on the product's container label. Exposure limits usually are given as parts per million (ppm) or milligrams per cubic meter (mg/m³ ). One PPM is like one drop of chocolate in 14 gallons of milk. Many chemicals can affect your body at 1 PPM or even smaller amounts.

Several organizations have published, required, or recommended safe working guidelines for exposures to hazardous chemicals. These organizations are OSHA, the National Institute of Occupational Safety and Health (NIOSH), and the American Conference of Governmental Industrial Hygienist (ACGIH).

Permissible Exposure Limits

PELs are exposure guides for airborne concentrations of regulated substances. They set limits upon a worker's inhalation exposure or the amount of substance a worker can legally breathe in a set amount of time.

There are three ways to represent PELs:

• Time weighted average
• Short-term exposure limit
• Ceiling limit

PELs are the only legally enforceable limits because they are set by OSHA. This means that by law, employers must keep a worker's exposure below the PEL. PELs are meant to offer the minimum levels of protection. However, more protective limits are always allowed.

Because PELs refer to inhalation exposures, they can not be used to determine exposure that occurs through the skin. A worker may have an exposure below the PEL but still become overexposed to a chemical through skin absorption.

The skin notation that is sometimes listed in the PELs means a chemical can be absorbed through the skin. It is not an exposure guide. There are no concentration guidelines for skin exposure. Therefore avoid skin contact with chemicals whenever possible, especially when the skin notation is used.

Note: PELs are important for protecting workers from overexposure to hazardous chemicals. However, workers should be aware of the drawbacks of PELs. Many PELs are not set to protect workers from chronic health effects such as cancer. In addition, PELs that apply to the construction industry were established in 1970. Although OSHA has updated PELs for some substances since that date, such as lead and asbestos, there are many PELs that are outdated.

Time Weighted Average

Time weighted average (TWA) is the average concentration of a substance in an area over an 8-hour work shift of a 40-hour work week. To determine a TWA, exposure levels are collected over a work shift. The exposure levels are averaged out for 8 hours and the results compared with OSHA's PEL lists. For example, a worker's exposure to toluene is 90 PPM for 2 hours, 120 PPM for 1 hour, and 20 PPM for 5 hours. The worker's actual exposure to toluene, averaged for the day is 50 PPM The calculations are shown in Figure 8-1. The allowable TWA exposure for toluene is 100 PPM Therefore, on this particular day, this worker was not overexposed according to OSHA limits.

 

TWA = (90 PPM x 2 hrs) + (120 PPM x 1 hr) + (20 PPM x 5 hrs) 8 hrs       TWA = 180 PPM hrs + 120 PPM hrs + 100 PPM hrs 8 hrs       TWA = 400 PPM hours 8 hrs       TWA = 50 PPM

Figure 8-1. Calculating the TWA.

Overtime Calculations

If a worker works longer than eight hours, overtime calculations must be done to determine the total exposure (Figure 8-2). Overtime does not allow an employer to expose a worker to higher concentrations. In fact, the worker must be exposed to lower concentrations because he/she will be working for a longer time period.

 

Overtime Calculations   Equation: PEL x 8 hrs hrs. worked     PEL = 100 PPM Hours Worked = 10   Calculation: 100 PPM x 8 hrs 10hrs = 80 PPM   Worker can only be exposed to 80 PPM for the duration of the time worked.

Figure 8-2. Overtime calculations.

Mixture Calculations

When a worker is exposed to more than one substance or to a mixture of substances that have similar chemical properties, mixture calculations must be done to determine the actual exposure. Chemicals with similar properties have a tendency to attack the same target organs which increases the chance of overexposure. Figure 8-3 gives an example of a mixture calculation.

 

1. Calculate exposure for each chemical:   Exposure = TWA PEL   Benzene TWA exposure is .5 PPM PEL = 1 PPM   .5 PPM 1 PPM = 50% of PEL Toluene TWA exposure is 80 PPM PEL = 100 PPM   80 PPM 100 PPM = 80% of PEL 2. Add exposures for each chemical to find total chemical exposure: TOTAL 50% + 80% = 130% Exposure is 130% of the PEL so the worker is overexposed. Exposure is 30% above the PEL so the worker is overexposed.

Short-Term Exposure Limits

Short-term exposure limits (STELs) are the maximum concentration levels that workers can be exposed to for a short period of time (usually 10 to 15 minutes) without suffering from adverse health effects. These health effects include:

• Irritation
• Chronic or irreversible tissue damage
• Dizziness sufficient to increase the risk of accidents, impair self-rescue, or reduce worker efficiency

STELs should not occur more than four times per shift, and there should be at least 60 minutes between exposures. The daily TWA PEL must not be exceeded.

Not all chemicals have assigned STELs. For substances without STELs, it's usually recommended that exposure should not exceed three times the PEL for a short term (10 to 15 minutes). For example, OSHA's PEL for perchloroethylene or perc is 25 PPM Perc has no STEL listed, so an STEL is estimated by calculating:
3 x 25 PPM = 75 PPM

Ceiling Limits

Ceiling limit (c) is an exposure level that should never be exceeded. However, not all chemicals have assigned ceiling values. If a ceiling limit is not assigned to a substance or chemical, it is generally recommended that exposures never exceed five times the PEL.

Threshold Limit Values

Threshold limit values are set by the ACGIH. They are based on the best available information from industrial experience, experimental human studies, and animal studies. The basis on which the values are established may differ from chemical to chemical. TLVs are only advisory and are not legally enforceable. A revised list of TLVs is published each year which makes them more current than PELs. However, chronic effects are not always given enough consideration in setting TLVs.

As with PELs, TLVs refer only to inhalation exposures. There are no concentration guidelines for skin exposure. Steps should be taken to avoid skin contact with chemicals, even if the TLV is within the standard. Overexposure to some chemicals can still occur by skin absorption.

Some chemicals cause adverse health effects if short-period exposures exceed a certain level. Special exposure limits are set for these chemicals. Ceiling limits (c) are levels of concentration or exposure that can never be exceeded. Immediately dangerous to life or health (IDLH) values identify an exposure level in an environment that is likely to cause death or serious health effects with very brief exposures.

Exposure Control Measures

Exposure control measures were developed to protect workers from chemical exposure and include:

• Substitution
• Engineering controls
• Administrative controls
• PPE

Substitution is the most desirable control measure because it eliminates the original hazard. The hazardous chemical is replaced with a nonhazardous or less hazardous chemical that works as well.

Engineering controls reduce or eliminate exposures by using mechanical means, such as ventilation systems, acoustical material, and clean air control booths. It does not eliminate the hazard.

Administrative controls reduce exposures to an acceptable limit in two ways:

1. Removing the worker from exposure after a specific length of time. This method is used extensively by the nuclear industry to reduce radiation exposures.
   
   
2. Establishing work rules, such as no eating, no drinking, or no smoking.

PPE is the least desirable exposure control measure because the hazard is still present so exposure is possible. However, it is also the most commonly used method in construction. PPE includes respirators, gloves, protective suits, boots, and other gear that are worn to protect workers from exposures. PPE is not an engineering control.

INVENTORY LISTS

Every employer who uses or stores hazardous chemicals on a job site is required to develop and make available a chemical inventory list. This list identifies the potentially dangerous chemicals that workers are exposed to on a work site. The chemical or product name located on the employer's chemical inventory list must be the same as the name on the container label and its corresponding MSDS. In this way, a worker can easily locate any additional information needed for protection.

The inventory list must be on the job site and available for a worker's review. It is updated whenever any new chemical or substance is brought to the site, or if a chemical is no longer used. A sample chemical inventory list is shown in Figure 8-4.

 

THIS COMPANY. INC. 111 MAIN STREET ANYWHERE, U.S.A. 12345   CHEMICAL INVENTORY LIST   Acrylic Water Base Paint (Lambert) Ater Blasting Shop Primer Red 53-R-101 Cosmiscoat Pavement Sealer Deck Paint Blue Gray 58-F-23 (Mobile Chemical Company) Deck Paint Brown 58-D-95 (Mobile Chemical Company) Deck Paint Ocean Gray 58-F-14 (Mobile Chemical Company) Duracrylic Extra High Gloss Thinner (PPG Industries) E Enton 37-127 Epoxy Resin (Reichold Chemical) E Enton 37-620 Epoxy Resin Hardener (Reichold Chemical) Paint Thinner 21-263 (PPG Industries) 2 - Propanol Solvent (Fisher) Styrofoam Plastic Forms (Dow Chemical) Varsol 1 Petroleum Solvent (Exxon) Varsol 18 Petroleum Solvent (Exxon)

MATERIAL SAFETY DATA SHEETS

A material safety data sheet (MSDS) is the primary source of information about hazardous chemicals used on a hazardous waste site. Employers are required to have an MSDS for every hazardous chemical used or stored on each job site. They must make the MSDSs available to workers or the workers' union representative for review.

MSDSs come in many different formats, but they all must contain the same basic information. Table 8-1 lists the minimum information that must be contained in every MSDS. Figure 8-5 shows a sample MSDS for the solvent WD-40^®.

Table 8-1. Minimum information needed on an MSDS.

MSDS Section Title	Information Included
Product Identity and Manufacturer's Information	Identity of the chemical (as on label) The name and address of the manufacturer Emergency phone numbers Date when MSDS was prepared
Hazardous Ingredients	Hazardous ingredients Properties of the chemical Common name and trade name OSHA PELs ACGIH TLVs Other recommended limits
Physical/Chemical Characteristics	Boiling point Vapor pressure and density Solubility in water Appearance and odor Evaporation rate Melting point
Fire and Explosion Hazard Data	Fire and explosion hazard data Flash point Flammable limits Extinguishing media Special firefighting procedures Physical hazards
Reactivity Data	Stability of the substance Conditions to avoid Incompatibility with other materials Hazardous decomposition properties Associated byproducts
Health Hazard Data	Acute (short-term) health hazards Chronic (long-term) health hazards Routes of entry Target organs Carcinogenicity (cancer-causing) Signs and symptoms of exposure Medical conditions aggravated Emergency first aid procedures
Precautions for Safe Handling and Use	Precautions for safe handling Precautions for safe use Spill containment procedures Waste disposal methods Precautions for storage
Control Measures	Exposure control measures Engineering controls Administrative controls Work practices Personal protective equipment

 

IDENTITY (as used on label and list) WD-40®

SECTION 1
Product Identification

SECTION 2
Hazardous Ingredients/Identity Information Hazardous Components (Specific)

SECTION 3
Physical/Chemical Characteristics

SECTION 4
Fire and Explosion Hazard Data

SECTION 5
Health Hazard/Routes of Entry

SECTION 6
Reactivity Data

SECTION 7
Spill or Leak Procedures

SECTION 8
Special Handling Information

SECTION 9
Special Precautions

SECTION 10
Transportation Data

SECTION 11
Regulatory Information

HAZARDOUS CHEMICAL LABELS AND LISTS

Under OSHA regulations, manufacturers, importers, and distributors of hazardous chemicals must label all products with information that identifies the specific hazards of the products. Employers may not remove these labels. If an employer transfers hazardous material into another container to be used by another employee for longer than one shift, the new container must also be labeled. Figure 8-6 shows two examples of product labels. Labels must include:

• Product name.
  
  
• Name, address, and phone number of the manufacturer, importer, or supplier.
  
  
• Hazards of the product including information such as:
  
  
  • Precautionary warning words, such as caution or warning.
    
    
  • Reactivity hazards of the product. For example, can the product be safely mixed with water?
    
    
  • Health hazards of the product, such as cancer-causing or respiratory irritant.
    
    
  • Target organs that might be affected by exposure, such as the lungs or kidneys.
    
    
  • Measures to protect the user, such as adequate ventilation or protective clothing.
    
    
  • Emergency first-aid information. For example, wash exposed areas with water for 15 minutes.

   

Information might be presented on the container in the form of a sign, symbol, or written word. Important warning words frequently used on labels include:

Caution:	Use with care. Workers are at some risk.
Warning:	The product presents more risk than one with a caution label.
Danger:	The most severe rating. The product presents a serious potential threat.

Figure 8-6. Examples of two product labels.

Special Labels

Although special labels are not required by the standard, employers may use them when hazardous chemicals are transferred from larger to smaller containers on the job site. These labels must not be removed or defaced because they provide important information. Figure 8-7 shows a typical label used for identifying hazardous materials with the Hazardous Materials Identification System (HMIS). The name of the product is listed and the appropriate boxes are marked under the headings:

• Target organs and effects
• Health hazards
• Physical hazards
• Route of entry

The label in Figure 8-7 has circles in front of health, flammability, reactivity, and protective equipment. These circles are filled in with a letter or number from the lists in the figure. Information from MSDSs, product labels, and Department of Transportation (DOT) or National Fire Protection Association (NFPA) labels are also used to fill out these special labels.

There may be other labels on a hazardous chemical container providing hazard information. The two most common labels are from the NFPA and the DOT.

National Fire Protection Association Labels

The NFPA label is a hazard system identification label developed to warn fire fighters about potential chemical hazards in a fire. It's commonly used today and provides important information to the worker.

The NFPA label is a diamond containing four squares in different colors. The squares are red, blue, yellow, and white. The red, blue, and yellow squares contain a hazard rating, ranging from 0 to 4, that indicates the severity of the hazard. The white square is reserved for symbols representing special hazards.

Figure 8-8 shows an example of an NFPA label and identifies the following:

• Color code designations
• Hazard ratings meanings
• Special hazard symbols

Table 8-2 is a more detailed explanation of the NFPA color codes and hazard rating information.

Note: An NFPA label does not cover chronic health effects. In addition, the names of the chemical, the product, and the manufacturer are not given.

Table 8-2. NFPA color codes and hazard rating information.

Health Hazard Color Code: BLUE Health hazards are noted in the blue square and are rated from 0 to 4, with 4 as the most dangerous.   Type of Possible Injury		Flammability Hazard Color Code: RED Fire hazards are noted in the red square and are rated from 0 to 4, with 4 as the most dangerous level.   Susceptibility of Materials to Burn.		Reactivity Hazard Color Code: YELLOW Explosion hazards are noted in the yellow square and are rated from 0 to 4, with 4 as the most dangerous level.   Susceptibility to Release of Energy
4	Extremely Hazardous (deadly) - very short exposure can cause death or major long-term injury.	4	Extremely Flammable (below 74°F or 22.8°C) - turns into a gas rapidly under normal conditions and burns easily.	4	Extremely Unstable (may detonate) - under normal conditions, this chemical may explode or react violently.
3	Highly Hazardous (extreme danger) - short exposure can cause serious temporary or possible long-term injury.	3	Highly Flammable (below 100°F or 37.8C) - liquid or solid can be ignited at almost any ordinary temperature.	3	Unstable (shock or heat may detonate or explode) - may react with water, or may need heating or another strong initiating source.
2	Moderately Hazardous (hazardous) - intense or continued exposure can cause temporary or possible long-term injury.	2	Moderately Combustible (between 100F and 200F or 37.8C and 93.3C) - must be heated somewhat or be in a very hot place before ignition can occur.	2	Unstable (violent chemical changes) - may react violently with water, or undergo violent chemical changes without exploding.
1	Slightly Hazardous (slightly hazardous) - exposure can cause irritation but only minor injury.	1	Slightly Combustible (above 200F or 93.3C) - must be heated before ignition can occur.	1	Unstable if Heated - normally stable, but can become unstable when hot or under pressure. Reactions with water are not violent.
0	No Health Hazard (normal) - 0 exposure under under fire conditions would offer no hazard beyond that of ordinary combustibles.	0	Nonflammable or Noncombustible - will not burn.	0	Stable - normally stable, even in fire. Does not react with water.

Department of Transportation Labels

The DOT label is used on containers and cartons of hazardous materials or products that are shipped across state lines. These labels are in addition to those required by OSHA regulations. A DOT label contains three types of information: color, hazard word, and hazard symbol. Figure 8-9 shows the DOT label for a corrosive chemical. The combination of color, hazard word and hazard symbol gives a great deal of information about the hazardous material. However, the DOT label does not identify the product's name, manufacturer, or chemical contents.

Figure 8-9. A DOT label for corrosive chemical.

Table 8-3 lists the color-coded backgrounds and hazard words used on DOT labels. Figure 11-10 shows the different hazard symbols used on the label.

When shipping hazardous materials, the severity of a hazard may be indicated on the shipping container. Hazards are divided into three packing groups:

Packing Group I	-	Great Danger
Packing Group II	-	Medium Danger
Packing Group III	-	Minor Danger

Table 8-3. Color-coded backgrounds and hazard words found on DOT labels.

Color Codes	Hazard Words
Orange	Explosive Blasting agent
Red	Flammable Combustible
Green	Nonflammable
Yellow	Oxidizer Oxygen Organic peroxide
White with red stripes	Flammable solids
Yellow and white	Radioactive
White and black	Corrosive
White	Poison Chlorine
Blue	Dangerous when wet
Special	Biological agent

CHEMICALS USED IN CONSTRUCTION

There are many hazardous chemicals used in construction that workers may be exposed to. Most of these chemicals are grouped into general categories of similar hazards. The most common categories of hazardous chemicals found on construction sites include:

• Acids, bases, and alkalis
• Adhesives and sealants
• Cleaners
• Concrete
• Fuels
• Solvents
• Wood

Acids, Bases, and Alkalis

Acids and bases (caustics) come in various forms-gases, liquids, and solids. Examples of common acids include sulfuric acid, hydrochloric acid, muriatic acid, and nitric acid. Commonly used bases (caustics) are lye (sodium hydroxide) and potash (potassium hydroxide). Both acids and bases can easily damage the skin and eyes. The seriousness of the damage depends on the strength of the chemical, length of contact, and actions taken.

Both acids and bases can be corrosive and can damage whatever material they touch. The more concentrated the chemical, the more dangerous it can be. Vinegar is a mild form of acetic acid and can be swallowed or rubbed on the skin with no damage. However, a concentrated solution of acetic acid causes serious burns.

Different acids react differently when they contact skin. Below are some examples:

• Mixing sulfuric acid with water produces heat. If sulfuric acid contacts skin, it reacts with the skin's moisture and burns.
  
  
• If hydrofluoric acid spills on the skin, a worker may not notice it. But hours later, the hydrofluoric acid will have worked its way through the skin and into the muscle tissue, causing deep burns. These burns are painful and take a long time to heal. If serious enough, they can cause death.
  
  
• Acids can damage the respiratory system when inhaled. Some acids in a gas or vapor form react with the moisture in the nose and throat causing irritation or tissue damage. Acetic and nitric acid vapors quickly penetrate the lungs causing serious damage.

In general, bases feel slippery or soapy. Soap is made from a mixture of a base (lye) and animal fat. Concentrated bases dissolve tissue easily and can cause severe skin damage on contact. Concentrated caustic gases, like ammonia, can damage the skin, eyes, nose, mouth, and lungs. Even dry powder forms of bases can cause damage when absorbed or inhaled, because they react with the moisture in the skin, eyes, and respiratory tract.

Always follow these rules when working with acids and bases:

• Know what chemicals are being worked with and how strong or concentrated they are.
  
  
• Use personal protective equipment, as required.
  
  
• In case of skin or eye contact, flush with cool water for at least 15 minutes. Do not rub skin or eyes.
  
  
• When mixing acids and water, always add the acid to the water to prevent splatter.
  
  
• Keep acids and bases apart. Store them separately and cleanup spills promptly. Acid and bases react, often violently, when mixed.

Cement and mortar are alkali compounds in their wet or dry form. As dust and powder, they can damage the skin and eyes when they react with moisture in the body. Cement and mortar also can cause allergic reactions in people who become sensitive to them.

Adhesives and Sealants

All adhesives and sealants have some type of hazard warning on the label. Because people often use them at home and on the job, warnings are taken lightly or ignored. However, adhesives and sealants are toxic because of their chemically reactive ingredients, or because of the solvent base that permits them to be applied more easily.

Adhesives or sealants that contain solvents may be flammable. Other types of adhesives, such as caulking or wood glue, may irritate eyes and skin. When working with any glue, avoid eye and skin contact. If the label says the adhesive is flammable, use and store it away from sources of ignition.

Epoxies contain epoxy amine resins and polyamide hardeners, each of which sensitizes skin and irritates the respiratory tract. Overexposure to epoxies can cause dizziness, drowsiness, nausea, and vomiting. Extreme or prolonged exposure can damage the kidneys and liver.

Flooring adhesives may contain acrylics that irritate the skin and cause nausea, vomiting, headache, weakness, asphyxia, and death. Other adhesives or sealants contain coal tar derivatives that are suspected of causing cancer. Avoid prolonged breathing of vapors or skin contact.

Cleaners

Cleaners contain acids, alkalis, aromatics, surfactants, petroleum products, ammonia, and hypochlorite. These ingredients cause cleaners to be irritating, and they can be harmful if swallowed or inhaled. Hazards from cleaners include:

• Health hazards (eye, nose, throat, skin, and lung irritation)
• Fire (some cleaners burn easily)
• Corrosive (cause severe skin damage)

Because of the variety of cleaning materials in use, there are many signs and symptoms of overexposure. Therefore, it is important for workers to read a product's MSDS to learn its specific signs and symptoms.

Many industrial cleaners are products commonly found in the home, so workers may underestimate the hazards they pose. Workers can protect themselves from these chemicals by taking the following actions:

• Read the labels and follow recommended precautions.
  
  
• Wear gloves and eye protection.
  
  
• Wash hands and face thoroughly before eating, drinking, or smoking.
  
  
• Do not inhale vapors or mists.
  
  
• Do not eat, drink, or smoke where vapors, mists, or dust are in the air.

Do not mix cleaning chemicals together unless specifically told to do so by a technical expert. Some chemicals can become deadly when mixed. For example, when bleach and ammonia or bleach and a drain cleaner are mixed, chlorine gas is produced. Chlorine gas is toxic and potentially explosive.

Concrete

Cement and lime, components of concrete, can cause adverse health effects such as skin irritation. The more lime in the cement, the more irritating it is to the skin. Cement that is even slightly moist can cause the skin to become hard, dry, and thick. The skin often cracks and can form ulcers. When water is added to cement, it produces heat which can also irritate and burn the skin. Cement dust also irritates the eyes, nose, and mouth. Use proper personal hygiene and the appropriate PPE to protect against cement's irritating alkaline effects.

Once concrete has cured or hardened, the health hazard to workers is dust which can damage the respiratory system. The dust is created when cutting concrete. Always try to use water to control the generation of dust. Also wear the appropriate respiratory protection to protect the lungs from the dust.

Fuels

The primary hazard posed by fuels is fire. Fuels are either flammable or combustible and should be handled with care. Follow these steps when handling fuel:

• Know the location of fire extinguishers, fire alarms, and evacuation procedures when dispensing or using fuels.
  
  
• Always store and transport fuel in approved, self-closing safety containers.
  
  
• Store gasoline and kerosene in properly marked containers. Never use kerosene containers for the transport or storage of gasoline.
  
  
• When filling portable containers with flammable materials, properly ground and bond the container to prevent ignition caused by static electricity.
  
  
• Use a bonding clamp to bond and ground containers when dispensing fuels.
  
  
• Check that spark-arrestors are in place when using portable containers.
  
  
• Remember, if a fuel is spilled, the vapors can travel some distance to an ignition source resulting in fire or an explosion.
  
  
• Do not store, use, or dispense fuel near arc welding or open flames.
  
  
• Do not pour waste fuel and flammable liquids down drains. See the MSDS for proper disposal procedures.

Excessive skin contact with fuels results in dermatitis. Fuels can enter the body through the skin, and over a long period, break down the fatty tissues and possibly build up in the body. Excessive inhalation of fuels may cause central nervous system depression and aggravate any existing respiratory disease. Leukemia, a blood disorder that usually causes death, is a potential side effect of chronic (long-term) exposure to fuels. Ingestion of fuels may cause poisoning and possible lung damage if aspirated into the lungs when ingested. Acute exposure to fuels may result in skin, lung, and respiratory tract irritation.

Workers can protect themselves from these chemicals by reading the labels and following the recommended precautions. Wear gloves and eye protection and avoid inhaling the vapors and mists. Wash hands and face thoroughly before eating, drinking, or smoking. Specific emergency first-aid procedures are given in the MSDS for fuels. In general, if fuel gets into the eyes, flush with clean running water for at least 15 minutes and then seek medical attention. If it gets on the skin, wash the area of contact.

Solvents

A solvent is a substance, usually a liquid, that can dissolve another substance. In construction, the most commonly used solvents are cleaners, degreasers, and thinners. There are two main classes of solvents:

1. Aqueous solvents (water-based), such as acids, alkalis, and detergents.
   
   
2. Organic solvents (carbon-containing), such as acetone, benzene, mineral spirits, toluene, trichloroethylene, and turpentine.

The two most common ways solvents enter the body are inhalation (breathing) or absorption (skin contact). Exposure to water based solvents results in health effects such as dermatitis and irritation. Excessive exposure to aqueous solvents in the form of mists can cause throat irritation or bronchitis.

Organic solvents cause more serious health effects, depending on the solvent and the exposure level. All organic solvents affect the central nervous system by acting as depressants or anesthetics. Effects can range from dizziness and headaches to respiratory arrest and death. Workers exposed to organic solvents can also experience:

• Nose, throat, eye, and lung irritation
• Damage to the liver, blood, kidneys, and digestive system

Upon contact with the skin, an organic solvent will dissolve the oils in the skin. The skin becomes dry and irritated, producing cracking, and skin rashes. Once a solvent penetrates the skin, it enters the bloodstream and can attack the central nervous system and other body organs. Like all chemicals, the effect a solvent has upon a worker depends on several factors:

• The chemical's toxicity
• Length of exposure
• The body's sensitivity level
• The solvent's concentration

Workers can protect themselves from solvent hazards by following these simple rules:

• Know what chemicals are being used.
  
  
• Wear appropriate PPE, such as gloves, safety glasses, and respirators to prevent contact with the skin, eyes, and lungs.
  
  
• Ensure the work area has plenty of fresh air.
  
  
• Avoid skin contact with solvents.
  
  
• Wash with plenty of soap and water if skin contacts the solvent.
  
  
• If a solvent splashes into the eye, flush with running water for at least 15 minutes and get medical help.

Wood

The primary concern regarding wood is pressure-treated lumber. The pressure treatment process uses inorganic arsenic, copper, zinc, a pesticide, or a combination of these, sometimes called CCA (chromated copper arsenate) to protect the lumber from decay and insect attack. The chemicals are forced deeply into the wood where they remain for a long time. As a result, treated wood, whether fresh from the lumber yard or found in an existing structure, can pose health hazards if not handled properly.

Avoid inhalation of sawdust from treated wood. Wear a dust mask when cutting, routing, sanding, or working with treated wood. Whenever possible, perform these operations outdoors to avoid indoor accumulations of airborne sawdust from treated wood. Keep bystanders, children, and pets from walking in the collected sawdust.

Some treated woods may appear damp and have chemical residue on the surface. Use gloves when handling freshly treated lumber and especially the sawdust from freshly treated wood.

Clean up all wood construction debris and dispose in ordinary trash collection. Do not burn pressure treated scraps in home stoves, fireplaces, or open fires, because the chemicals may become part of the smoke and ashes. Treated wood may be burned in commercial and industrial incinerators or boilers, according to state and federal regulations. Do not use treated wood in circumstances where the wood will come in direct contact with food or with public drinking water sources.

Acute allergic reactions have been reported following contact with mahogany, birch, beech, and other untreated woods. These reactions include hives, respiratory tract irritation, and general swelling. To reduce the likelihood of such a reaction, use good personal hygiene. Wash hands and face thoroughly. Take meals and breaks away from the work area. Upon completion of work, remove work clothing and launder separately from non-work clothing. Shower thoroughly to remove any material in contact with skin.

TYPICAL CONSTRUCTION HAZARDS

Table 8-4 provides a review of the typical hazardous substances used in construction. Hazardous substances are arranged by classes with information on each class summarized in the table. The table covers the following areas:

• Class - group of similar substances used for the same purpose, such as abrasives or fuels.
  
  
• Examples - identifies examples of the commonly used substances in each class.
  
  
• Routes of Entry - identifies how a particular substance enters the body. Routes of entry include:
  
  
  • Inhalation (breathing)
  • Ingestion (swallowing)
  • Absorption (skin)
  • Skin or eye contact
    
    
• Physical Hazards - describes the hazards a substance holds for workers, such as explosive, flammable, or compressed gas.
  
  
• Health Hazards - explains the health effects a substance may have if workers are exposed to it. Examples include irritating to skin, cancer-causing and infectious.
  
  
• Target Organs - identifies which organs in the body are affected by exposure to the hazardous substance.
  
  
• How Detected - a general guide as to how workers might recognize this group of substances. For example, fuels are usually liquids that have a characteristic odor that is easily recognized.
  
  
• Types of Protection - provides some general guidelines for workers on protecting themselves from exposure, such as respirators and ventilation to protect the lungs. It notes when a substance can be transferred from the air or hands to food, drink, or smoking materials.

Use this table as a general review of hazardous chemical information. Always review the MSDSs for hazardous chemicals used on the job site, especially when a chemical is used for the first time. The MSDS may differ from the information in the table. Follow the MSDS.

There are many hazardous chemicals used in construction. Other construction trades are exposed to a few of these chemicals. However, construction laborers may be exposed to all of them.

Table 8-4. Hazardous substances used in construction.

Note: This table is only a general overview of typical hazardous substances used in construction. The substances listed here may not be the same as you use on the job site. Therefore, you should review the MSDS for each product you use, especially the first time you use it.

ASSIGNMENT SHEET

1. Define the following terms or words:

Administrative controls

Engineering controls

Substitution

Time weighted average

2. Identify the following acronyms: ACGIH DOT IDLH MSDS NFPA NIOSH PEL TWA 3. List the requirements of the Hazard Communication Standard's written program. 4. List the basic information that must be covered in the employer's training program for hazard communication. 5. List the information an employer must provide each employee. 6. List exposure control measures that protect workers from exposure. 7. Demonstrate how to use MSDSs by answering the following questions. (Use Figure 8-5 Sample MSDS) a. What is the name of the product? b. List the hazardous components of this product. c. Is this product lighter than air? Yes No d. What is the appearance and odor of this product e. What is the flash point of this product? f. Is this product flammable or combustible? g. What is the extinguishing media for this product? h. Does this product contain cancer-causing components? Yes No i. Is respiratory protection required while using this product? Yes No j. What other PPE is to be used with this product? k. What special precautions should be taken when using this product? l. When was this MSDS revised? m. What is the emergency phone number for this product? n. Is emergency and first-aid information given? Yes No 8. List the information that must be given on a typical label. 9. List the three basic types of labeling systems. 10. Demonstrate how to read a label by answering the following questions. (Use either label in Figure 8-6.) a. What is the name of the product? b. Who makes it? c. What is the physical hazard from this product? d. What are the health hazards? e. What are the target organs? f. What are the safe handling recommendations? g. What measures are to be used to limit worker exposure? h. What is the first aid information given? 11. Complete the following questions using the chart. The chart describes a worker's exposure during a single working shift on a structural steel lead abatement job site. What is this worker's TWA for this particular day? Identify the worker's exposure given that the PEL for lead is 50 µg/m3 ? Identify the worker's exposure if the PEL for lead was lowered to 30 µg/m3 ?