The use of epoxy coating systems continues to expand in popularity, with epoxies valued for strong adhesive properties, chemical and heat resistance, and toughness. But coatings applicators need to understand the potential risks of using epoxy products and know how to safely handle and apply these systems.
While potential health effects vary based on the type and duration of exposure, there are clear steps that applicators can and should take to mitigate the hazards. Epoxy systems can be used safely as long as appropriate ventilation, work practices, proper hygiene, and personal protective equipment (PPE) are considered.
Epoxy resin systems are chemical mixtures containing at minimum two parts: the epoxy resin and a curing agent. The most common epoxy resins are the glycidyl ethers of alcohols. A popular liquid epoxy resin is the bisphenol-A diglycidyl ether (DGEBA), and it accounts for more than 75 percent of the epoxy resins used in industrial applications. Meanwhile, the most common curing agents come from a large class of compounds known as amines. Among amines, polyamide and cycloaliphatic amine curing agents may be less hazardous than simpler aliphatic chemicals.
When cured, these chemicals form a hard, durable plastic material known as epoxy. The systems may also contain other chemicals, including solvents, pigments, and fillers. In single-component epoxy systems, the potentially hazardous monomers are already partly reacted. In two-part epoxy systems, the monomers react when they’re mixed together. Reduced-solvent content or solvent-free products are also on the market. Once finished and cured, epoxies are usually only hazardous if they are burned, cut, or sanded.
The potential health hazards associated with epoxy systems vary. They can contribute to a sensitization to epoxy. Types of exposure include skin and eye irritation, allergic skin reactions, respiratory tract (nose, throat, and lungs) irritation, and allergic respiratory reactions, asthma-like symptoms, or breathing difficulties. These problems generally occur through inhalation of the epoxy or if the epoxy makes contact with the skin or eyes. Prolonged or repeated exposure may add to the risk of the applicator’s injury or illness.
Epoxies may also pose a greater risk for pregnant women, according to the U.S. Centers for Disease Control and Prevention (CDC). The CDC notes that some of the chemicals used in epoxies have been linked with a heightened risk for fertility problems, miscarriage, stillbirth, and birth defects.
The U.S. Occupational Safety and Health Administration (OSHA) requires the vendor or manufacturer of epoxy products to provide applicators with a Safety Data Sheet (SDS) for each of its products. Applicators should refer to that sheet for specific details on each product and the symptoms of possible related health effects.
The first step to resolve any safety issue is to try to engineer it out of the jobsite. With epoxy systems, the labels often instruct applicators to apply the product with adequate ventilation. This can help to keep chemical vapors from building up in the work area. According to CPWR, The Center for Construction Research and Training, one important step in adequately ventilating a work area is the use of local exhaust ventilation throughout the process, including the surface preparation phase. For example, local exhaust systems on floor grinders and sanders can capture dust before it enters the work area.
As a complementary option, dilution ventilation during application can also help reduce the level of chemical vapors. Specifically, the use of fans and open windows can bring fresh air into work areas. For example, a portable exhaust fan attached to a flexible hose may be effective at reducing exposure to epoxy vapors; however, applicators must be careful to place the fan very close to the work area to draw air away from the workspace, all the while making sure that the fan does not redirect harmful vapors toward any other workers or into another occupied space.
Another step to mitigate exposure to epoxies involves proper work practices. One tip from CPWR is to use disposable containers, rather than bowls, for mixing and pouring. This can reduce the chemical handling by applicators during the clean-up process. A second way to reduce exposure is to purchase resins and hardeners in packaging that allows the applicator to mix the ingredients together before opening the bags.
Good housekeeping is a simple method that can also help to prevent exposure. According to CPWR, goals include keeping work and storage areas uncluttered and clean; keeping chemical containers tightly covered when not in use; wiping up spills with cotton rags or other absorbent materials promptly and then disposing of the rags in closed containers; cleaning tools after use; providing a changing area where workers can change out of work clothes and keep street clothes separate; and providing a clean area for breaks and lunch, separate from the epoxy area. These practices may help keep the epoxy parts and systems contained in one area.
Workers and supervisors should be trained on the need for good housekeeping, and they should be allotted enough time by management for regular clean-up activities during each shift. For example, workers might not quickly wipe up spills and immediately dispose of any materials used to clean it up, should the timetable of the job feel rushed. Management should also regularly provide housekeeping supplies for these activities, including brooms, mops, chemical absorbers for floors, water, and waste receptacles.
Personal Protective Gear
Applicators should always follow the manufacturer’s recommendation on PPE when working with high-performance coatings, specifically epoxy products. Some general PPE recommendations for handling, mixing, and applying epoxy systems are:
• Eye Protection: Chemical goggles with side shields to protect against splashes, or goggles with an 8-inch (203.2 mm) minimum full-face shield should be worn.
• Gloves: Options for hand protection include ethylene vinyl alcohol (EVOH) laminate, butyl rubber, nitrile rubber, or neoprene. Cotton and latex gloves, as well as barrier creams, are not sufficient to protect installers from epoxies. Applicators should wash and dry their hands before and after each use of gloves by using clean running water, a mild soap (pH neutral or slightly acidic), and clean towels.
• Sleeves: Protective sleeves should be worn with gloves to protect the person’s arms from chemical contact and splashes.
• Coveralls: To prevent epoxy chemicals from soaking into an installer’s clothing and contacting his or her skin, coveralls should be worn over work clothes. Coveralls can also protect the skin from powdered materials like aerosols, as well as light liquid splashes.
• Aprons: Chemical-resistant aprons, such as those made with butyl rubber, can be used as additional protection with coveralls.
• Boots: Use with pants taped inside to help protect the skin and prevent chemicals from entering through the top of the boots.
• Respirator: Options include an organic vapor respirator, a full-face air purifying respirator for organic vapors, or a self-contained breathing apparatus. This should be used in consultation with the manufacturer’s use limitations. All respiratory protection must be used in accordance with the OSHA Respirator Standard, 29 CFR 1910.134.
• Jewelry: Any jewelry should be removed when on the job, since chemicals can collect under rings, watches, and necklaces.
• Changing clothes: Workers should change into clean clothes at the end of the shift, before leaving work. This protects against the risk of the epoxy spreading to an automobile interior. If the clothes cannot be left at the job, they should be taken home in a separate, sealed container.
Applicators are increasingly turning to epoxy coatings due to their strong adhesive properties, as well as their ability to strengthen structures and add decorative effects to treated surfaces. Although there are potential health hazards associated with the use of epoxy coatings, much as with many other coatings, these may be mitigated through the use of engineering controls, best work practices, and proper PPE. As always, a safety expert should be consulted for specific guidelines and practices. For more information, contact: OSHA, www.osha.gov