Epoxy flooring safety: chemicals, dust, PPE and the OSHA rules that apply

The main hazards on an epoxy floor job are chemical and physical: epoxy hardeners that burn skin and cause allergic reactions, isocyanates in polyaspartic and other urethane-type topcoats that can cause asthma, flammable cleanup solvents, silica dust from grinding, and slips on wet coating. The protection is consistent: keep resin off your skin, protect your eyes and lungs, ventilate, and read each product’s safety data sheet before you open it. A respirator with organic-vapor cartridges and particulate filters costs about $23–52.

The OSHA requirements below apply to employers, and they’re part of setting up any coating company, covered in how to start an epoxy flooring business. This is a summary, not legal or medical advice: follow each product’s SDS and data sheet, and confirm requirements with OSHA, your state plan or a safety professional.

The hazards at a glance

Epoxy hardeners: burns and skin allergy

The hardener side of an epoxy kit carries the stronger warnings. The resin side (Part A) is usually labeled “Warning” as a skin and eye irritant and skin sensitizer. The hardener (Part B) is often labeled “Danger”: it can cause severe skin burns and eye damage, may cause an allergic skin reaction, is harmful if swallowed, and some hardeners are suspected of damaging fertility or the unborn child. Hardener SDSs call for protective gloves and tightly sealed goggles.

“Allergic skin reaction” is the warning to take most seriously over a career. Sensitization happens in two phases: first the immune system learns to react, then later exposures trigger the allergic response, and a sensitized person usually reacts to lower levels than it took to sensitize them. In plain words: once you’re sensitized, it takes less to set you off. Keeping resin off your skin from your first job is the protection.

Practical rules:

• Wear chemical-resistant gloves for mixing, application and cleanup. High-quality nitrile is the standard for 100%-solids epoxies; the glove material has to be impermeable to the product, and breakthrough times come from the glove maker.
• Wear goggles or safety glasses with side shields while mixing; splashes happen at the bucket.
• Cover your arms and legs with disposable coveralls, and change them when they’re soaked through.
• Never use solvent to clean resin off skin. Wash with soap and water.

Isocyanates in polyaspartic, polyurea and polyurethane

The activator side of most polyaspartic, polyurea and polyurethane coatings is an isocyanate, typically an HDI-based polyisocyanate with a small amount of hexamethylene diisocyanate. Its SDS warnings read: toxic if inhaled; may cause allergy or asthma symptoms or breathing difficulties if inhaled; may cause an allergic skin reaction; wear respiratory protection if ventilation is inadequate.

The main effects of hazardous isocyanate exposure are occupational asthma and other lung problems, along with irritation of the eyes, nose, throat and skin. Isocyanates can sensitize workers so that a later exposure brings on a severe asthma attack, and both breathing them and skin contact can cause sensitization. Engineering controls, such as ventilation, are the main way to keep exposure down.

For a garage job that means: move air through the space with fans exhausting outdoors, keep people who aren’t working out of the room, wear the respiratory protection the SDS calls for, and protect skin as carefully as with epoxy. Anyone with persistent or recurring cough, wheezing, shortness of breath or chest tightness should see a physician who knows work-related illness; spotting sensitization early and cutting off exposure completely reduces the risk of long-term lung problems. Which topcoats contain isocyanates, and why contractors use them anyway, is covered in polyaspartic vs epoxy.

Solvents, VOCs and fire

Most professional floor coatings are now high-solids or 100% solids: a 100%-solids epoxy has 0 g/L of VOC, and a high-solids polyaspartic under 50 g/L. The solvents arrive at cleanup: acetone or xylene are the usual choices for cleaning tools. Acetone has a flash point of 0°F, so its vapor can ignite at any temperature you’ll work in. Keep solvent containers closed, use only what you need, keep them away from water heaters, furnaces, pilot lights and anything that sparks, and dispose of solvent-soaked rags as the product’s SDS and local rules require.

Keep fuel-burning engines and heaters out of the work area too. Carbon monoxide from gas and propane engines and heaters can overcome a worker in minutes in an enclosed space, and a garage counts.

Silica dust from grinding

Grinding concrete releases respirable crystalline silica, particles at least 100 times smaller than ordinary sand, which can cause silicosis, lung cancer, chronic obstructive pulmonary disease and kidney disease. OSHA’s silica standard for construction (29 CFR 1926.1153) sets the controls for grinders and the employer’s duties: a written exposure control plan, a competent person, housekeeping without dry sweeping, and medical exams for workers who must wear respirators 30 or more days a year. The details are in dust extractors and OSHA’s silica rules.

Slips and falls

Wet coating is slick. Wear spiked shoes on wet epoxy and polyaspartic, and keep cords and vacuum hoses out of walkways. The finished floor matters too: there’s no single federal number for slip resistance, but the ANSI A326.3 standard sets a wet dynamic coefficient of friction of 0.42 or more for level interior floors that get walked on wet. For ramps, wet areas and commercial floors, ask the manufacturer for its slip-resistance options.

PPE by task

A half-face respirator with organic-vapor cartridges plus P100 particulate filters covers resin vapor and grinding dust in one mask; a reusable kit costs about $23–52. Whether that’s adequate for a given product is a question for its SDS and, for employers, the respirator program below.

What OSHA requires of employers

Who’s covered. OSHA covers employers and their workers; self-employed people are not covered by the OSH Act. The rules start the day you hire help. Many states run their own OSHA-approved State Plans, which must be at least as effective as federal OSHA and can have different or more stringent requirements.

Respiratory protection, 29 CFR 1910.134 (applied to construction by 29 CFR 1926.103). Where respirators are necessary or required by the employer, the employer must:

• Establish a written respiratory protection program with worksite-specific procedures.
• Provide a medical evaluation before the employee is fit tested or required to use the respirator.
• Fit test tight-fitting respirators before first use, whenever a different facepiece is used, and at least once a year.
• Keep tight-fitting respirators off workers with facial hair that comes between the seal and the face.
• For vapor cartridges without an end-of-service indicator, set a cartridge change schedule based on objective data.

Even voluntary use has rules: workers who choose to wear a respirator must get OSHA’s Appendix D information, and voluntary use of anything beyond a filtering facepiece (dust mask) still needs a medical evaluation and proper cleaning and storage.

Hazard Communication, 29 CFR 1910.1200 (identical in construction under 29 CFR 1926.59). Employers must keep a written hazard communication program, keep a safety data sheet for each hazardous chemical readily accessible during every shift, and train employees on the hazardous chemicals in their work area when they’re first assigned and whenever a new hazard is introduced. A phone with the SDSs saved works, as long as nothing stands in the way of immediate access.

First aid: read Section 4 before you need it

Every SDS has the same 16 sections, and Section 4 is first aid. For epoxy and isocyanate products, it typically says:

• Skin (epoxy hardener): remove contaminated clothing, wash immediately with soap and water, and get medical treatment for burns.
• Eyes (epoxy hardener): rinse the open eye under running water for at least 15 minutes; see a doctor if symptoms persist.
• Breathing (isocyanate activator): move the person to fresh air and get medical attention; it may cause an allergic respiratory reaction.
• Swallowed (epoxy hardener): drink plenty of water and call a doctor immediately.

Keep an eyewash bottle and a gallon of clean water in the truck, and the SDSs where everyone can reach them; the job-day checklist is a good place to confirm both before work starts. Isocyanate SDSs list eyewash stations, showers and ventilation as the engineering controls to have in place.