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Chemical Hazards



Construction workers are exposed daily to various health hazards on the construction site. Covering all of the health hazards in construction is outside the scope of our training in this course, but we will cover some of the hazards to which workers will be exposed.

Hazard Communication Program

hazard communication
Sample Label
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One program that helps to prevent illness due to exposure to health hazards is the Hazard Communication Program. The purpose of OSHA’s hazard communication standard (HCS) is to ensure that all hazardous chemicals are evaluated and the information is transmitted to employees via a hazard communication program.

The HCS applies to all hazardous chemicals to which employees may be exposed under normal conditions of use, or in a foreseeable emergency. A “hazardous chemical” is any chemical that presents a physical or health hazard.

Contractors’ employees must also be informed about the hazardous chemicals they may be exposed to. The employer’s written hazard communication program must include all of the following:

  1. the methods the employer will use to provide contractors’ employees on-site access to safety data sheets (SDS)
  2. the methods to inform them of any precautionary measures
  3. the methods to inform other employees of the labeling system used in the workplace

The employer must ensure that each container of hazardous chemicals in the workplace is labeled, tagged, or marked to identify the hazardous chemicals and appropriate hazard warnings.

The employer must maintain copies of the required SDS for each hazardous chemical, and must ensure that they are readily accessible during each work shift by employees when they are in their work areas.

If employees must travel between workplaces during a work shift, the SDS may be kept at the primary workplace facility; however, the employer must ensure that employees can immediately obtain the required information in an emergency.



Failure to recognize the hazards associated with chemicals can cause chemical burns, respiratory problems, fires and explosions on construction sites.

Health hazards: Hazardous chemicals can produce acute and/or chronic (short-term and/or long-term) illness and other health issues. Some examples of hazardous substances that can cause illness include:

  • carcinogens
  • toxic agents
  • irritants
  • corrosives
  • sensitizers

Physical hazards: Hazardous chemical physical hazards produce injuries. Some examples include:

  • combustible liquids
  • compressed gases
  • explosives
  • flammables
  • organic peroxides
  • oxidizers
  • unstable (reactive) agents

General Precautions and Safe Work Practices

safety data sheets

Recommended precautions and safe work practices to protect employees from exposure to hazardous chemicals include the following:

  • Maintain a Safety Data Sheet (SDS) for each chemical used in the facility.
  • Make this information accessible to employees at all times in a language and format that are clearly understood by all affected personnel.
  • Train employees on all requirements of the hazard communication program, including how to read and use the SDS.
  • Follow manufacturer's SDS instructions for handling hazardous chemicals.
  • Train employees about the risks of each hazardous chemical being used.
  • Provide spill clean-up kits in areas where chemicals are stored.
  • Have a written spill control plan.
  • Train employees to clean up spills, protect themselves and properly dispose of used materials.
  • Provide proper personal protective equipment and enforce its use.
  • Store chemicals safely and securely.
  • Develop and maintain a written hazard communication program addressing Safety Data Sheets (SDS), labeling and employee training.
  • Label each container of a hazardous substance (vats, bottles, storage tanks) with standardized Globally Harmonized System (GHS) labeling.

Exposure to Lead


Employers need to determine whether their workers will be exposed to lead on the construction worksite. This initial determination is done by sampling the air they breathe with special equipment. This is called air monitoring (also, exposure monitoring). It’s important to know the following to help protect workers:

  • Action level: The exposure level at which you must act to protect your employees. Thirty micrograms per cubic meter of air (30 µg/m3) averaged over an eight-hour period is the action level for lead exposure.
  • Permissible exposure limit: The permissible exposure limit (PEL or OSHA PEL) is the legal limit for exposure to a chemical substance or physical agent. The employer must make sure that no employee is exposed to lead at concentrations greater than fifty micrograms per cubic meter of air (50 ug/m3) averaged over an 8-hour period.
  • Trigger tasks for Lead: Tasks that expose workers to extreme amounts of lead and trigger a set of interim measures employers must take to protect those workers. If employees do any of these tasks, assume they’re exposed to lead at levels above the PEL until you’ve done an initial determination.

The following tasks can expose workers to extreme amounts of lead:

  • cutting with a torch
  • heat gun work
  • manual sanding
  • manual scraping of dry materials
  • sanding with a dust collection system
  • spray painting
  • manual demolition of structures such as dry wall, windows, and siding
  • sanding without dust collection systems
  • abrasive blasting
  • lead burning
  • torch burning
  • welding

Protective Measures for Lead


If your employees do trigger tasks, you must provide them with all of the following until you can show they are exposed below the action level:

  • Make sure workers wear appropriate respirators.
  • Provide adequate protective clothing.
  • Clean areas for changing and storing clothing.
  • Ensure workers have access to hand washing facilities.
  • If necessary, provide blood sampling for lead.
  • Conduct training that covers lead health hazards and protective measures.

Exposure to Methylene Chloride (MC)


About 9,505 construction companies use products that contain the hazardous chemical, methylene chloride. Exposure often happens when workers are stripping paint or other coatings, applying foam, painting with epoxy paint, cleaning equipment with solvents, and spraying adhesives.

Workers are more likely to be exposed to high levels of MC when working in small, enclosed spaces that are not well ventilated.

Exposure may occur through inhalation, by absorption through the skin, or through contact with the skin. OSHA considers methylene chloride to be a potential occupational carcinogen.

The following describes some engineering controls and work practices you may find helpful in reducing worker exposures to MC at your site.

Workers in this photo are using MC to strip bathtub for refinishing.
  • Keep MC Vapors contained. Store and transport MC products only in approved safety containers.
  • Instruct and train employees to be aware of hazards, personal hygiene, and how to use personal protective equipment.
  • Instruct employees handling or using flammable liquids, gases, or toxic materials in the safe handling and use of these materials.
  • Avoid breathing the air directly above areas covered with MC.
  • Avoid direct skin contact with MC. Wear two pairs of gloves when using stripping solution. The inner glove should be made of polyethylene (PE)/ethylene vinyl alcohol (EVOH), PE, or laminate to prevent MC penetration. The outer glove should be made of nitrile or neoprene to protect against puncture or rips. Wear a face shield or goggles to protect your face and eyes.
  • Use the washing facilities in your work area to wash off any MC from your hands and face. Use lots of soap or mild detergent and water to clean grease, oil, dirt, or anything else off your skin. Do not use MC or other organic solvents to clean your skin.
  • Minimize the chance of spills and leaks. Develop and follow procedures for containing MC spills or leaks.
  • Take extra precautions in low and confined spaces. MC vapors are heavier than air, so they tend to move to low, unventilated spaces.

Check out more detailed information on Methylene Chloride from the EPA.

Exposure to Chromium

spray painters
Spray painters are applying a conversion coating treatment on the outside of an F15.

Chromium is a steel gray, lustrous, hard metal extracted from chromite ores. Chromium VI (hexavalent chromium) is of principal concern because of its extreme toxicity and designation as a human carcinogen.

In 2011, it is estimated 558,000 workers are potentially exposed to Cr(VI) in the United States. US production of chromium was estimated at 160,000 metric tons, coming almost entirely from recycling stainless steel scraps.

Some major industrial sources of hexavalent chromium are:

  • chromate pigments in dyes, paints, inks, and plastics
  • chromates added as anti-corrosive agents to paints, primers and other surface coatings
  • chrome plating by depositing chromium metal onto an item’s surface using a solution of chromic acid
  • particles released during smelting of ferrochromium ore
  • fume from welding stainless steel or non-ferrous chromium alloys
  • impurity present in Portland cement
Hexavalent Chromium Exposure Control - UW/WISHA

Workers performing the following tasks are potentially exposed to Cr(VI). Workplace exposures occur mainly in the following task areas:

  • welding and other types of hot work on stainless steel and other metals that contain chromium
  • use of pigments, spray paints and coatings
  • operating chrome plating baths

Workplace exposure to hexavalent chromium may cause the following health effects:

  • lung cancer in workers who breathe airborne hexavalent chromium
  • irritation or damage to the nose, throat, and lung (respiratory tract) if hexavalent chromium is breathed at high levels
  • irritation or damage to the eyes and skin if hexavalent chromium contacts these organs in high concentrations

Safety Precautions


To protect employees from the hazards associated with Hexavalent Chromium, employers should do the following:

  • Limit the eight-hour time-weighted average exposure to chromium VI (hexavalent chromium) to five micrograms per cubic meter of air (5 ug/m3).
  • Perform periodic monitoring at least every 6 months if initial monitoring shows employee exposure at or above the action level (2.5 micrograms per cubic meter of air calculated as an 8-hour time-weighted average).
  • Provide appropriate personal protective clothing and equipment when there is likely to be a hazard present from skin or eye contact.
  • Implement good personal hygiene and housekeeping practices to prevent hexavalent chromium exposure.
  • Prohibit employee rotation as a method to achieve compliance with the exposure limit (PEL).
  • Provide respiratory protection as specified in the standard.
  • Make available medical examinations to employees within 30 days of initial assignment, annually, to those exposed in an emergency situation, to those who experience signs or symptoms of adverse health effects associated with hexavalent chromium exposure, to those who are or may be exposed at or above the action level for 30 or more days a year, and at termination of employment.

For more information, take OSHAcademy Course 705, Hazard Communication Program.


Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. A hazardous chemical is any chemical that _____.

2. What is the term used to describe the legal limit for exposure to a chemical substance or physical agent?

3. The Action Level for exposure to lead is _____ averaged over an 8-hour period.

4. What is a helpful method to reduce exposure to methylene chloride (MC)?

5. Which of the following tasks may expose workers to Chromium VI (hexavalent chromium) in the workplace?

Have a great day!

Important! You will receive an "error" message unless all questions are answered.