U.S. Department of Labor
Process: Surface Preparation and Preservation
Application of Toxic Coatings, Paint Strippers and Solvents
Many workers are exposed to hazardous and toxic solvents on a daily basis. Health hazards associated with solvent exposure include toxicity to the nervous system, reproductive damage, liver and kidney damage, respiratory impairment, cancer, and dermatitis.
Hazardous and toxic substances, used in coatings, paint strippers, and solvents, are defined as those chemicals present in the workplace which are capable of causing harm. In this definition, the term "chemicals" includes dusts, mixtures, and common materials such as paints, fuels, and solvents. "Solvents" refer to liquid organic chemicals used to dissolve solid materials, and can be made from natural sources such as turpentine and citrus solvents. However, most are derived from petroleum or other synthetic sources. Solvents are used widely because they dissolve materials like resins and plastics, and they evaporate quickly and cleanly.
Hazards associated with applying coatings include toxic exposures, fire, and explosions. As types of coatings and work practices evolve, these hazards are being reduced or eliminated. Modern paints and coatings often have higher flash points, which has helped to reduce the risk of fire and explosion. The improvement of atmospheric monitoring equipment has allowed for better detection of toxic and explosive atmospheres. Injury, illness, and fatality statistics reflect this trend of improved hazard control during surface preparation and preservation activities. However, coatings made with new chemicals that are not yet fully understood may pose risks to the health of workers. As a result, it is important to protect workers from exposure to these coatings.
Proper ventilation combined with respirator use is the most effective method to protect workers from exposure to toxic or hazardous substances in airborne gasses, vapors, and aerosols (spray). Air-purifying and air-supplied respirators are commonly used to prevent the inhalation of toxic compounds.
During cleaning operations where toxic solvents are used, OSHA requires that at least one, or a combination, of the following safety precautions be implemented: (1) enclose the operation to ensure that no toxic vapor escapes into surrounding areas; (2) use an effective means of natural or mechanical ventilation to remove the vapor at the source, and dilute the concentration of vapors in the space to a safe level; and (3) ensure that workers are equipped with and use suitable respiratory protection to protect them against toxic vapors, and where necessary, against exposure to skin and eye contact with toxic solvents and their vapors by necessary clothing and equipment (29 CFR 1915.32(a)(1) through (a)(3)). Further, a hazard assessment must be performed to identify and select the appropriate PPE (29 CFR 1915.152(b)(1)). In addition, employers must train workers on how to use the required PPE (29 CFR 1915.152(e)).
Even when employers take the above safety precautions, workers may still develop sensitivity to airborne gasses, vapors, and aerosols (spray) used in the workplace. A common sensitivity involves isocyanates, which are compounds that make up all polyurethane products. Jobs in the shipbuilding and ship repair industry that may involve worker exposure to isocyanates include painting, use of adhesives, and the application or removal of insulation materials or surface coatings. The main effects of hazardous exposures are occupational asthma and other lung problems, as well as irritation of the eyes, nose, throat, and skin. Once a worker has developed sensitivity, even low concentrations can trigger symptoms. It is recommended that workers who have developed sensitivity be assigned to areas where no exposure is possible, or be provided with supplied-air respiratory protection and PPE to prevent any dermal (skin) exposure.
Where coatings, liquids, or solvents are capable of producing a flammable atmosphere under the conditions of its use, frequent atmospheric tests must be performed by a competent person to ensure the concentration of flammable vapors are kept below 10 percent of their lower explosive limit (LEL). If the vapor concentration is above this level, ventilation, at sufficient quantities, must be used to bring the concentration below it. Other precautions that employers must implement are (29 CFR 1915.36):
- Prohibiting personnel from smoking in the work area.
- Eliminating the use of equipment with open flames, or that produce arcs or sparks.
- Storing scrapings and rags soaked with flammable liquids in covered metal containers.
- Permitting only the use of explosion-proof lights (approved by UL for Class I, Group D atmospheres, or approved as permissible by MSHA or the U.S. Coast Guard).
- Ensuring power or lighting cables in use are free of cracks and worn spots, and have no connections within 50 feet of the operation. Do not overload electrical cables and handle with care to prevent undue stress or chafing. The employer must have a competent person inspect the lines to ensure these conditions are met.
- Supplying suitable fire extinguishing equipment with immediate access and kept ready for use in the event of a fire occurs.
For more information:
|Ventilation Purpose, Uses, and Requirements||Ventilation in Shipyard Employment Guidance Document|
|Recognizing Potential Hazards and Relevant Safety Standards Related to Isocyanate Exposure||OSHA Webpage – National Emphasis Program for occupational Exposure to Isocyanates|