COSHH Assessment for Adhesives and Resins: Epoxy, PU, and Contact Adhesives

Adhesives and resins are everywhere on construction sites. Flooring installers use epoxy screeds and PU adhesives. Electricians pot components in resin. Plumbers seal joints with solvent-based contact adhesives. Roofers apply polyurethane foam insulation. Each product carries different chemical hazards, and a generic COSHH assessment will not cover them properly.

This guide breaks down the specific risks of each adhesive family and explains what your COSHH assessment needs to include for each one.

Types of Adhesives and Their Hazards

Construction adhesives fall into several families, each with distinct hazard profiles:

Epoxy resins are two-part systems (resin plus hardener) used for structural bonding, floor coatings, and waterproofing. The resin component contains bisphenol A diglycidyl ether (BADGE), a potent skin sensitiser. The amine hardeners are corrosive and also sensitising. Once a worker develops epoxy allergy, it is permanent and career-altering.

Polyurethane (PU) adhesives and foams contain isocyanates, primarily methylene diphenyl diisocyanate (MDI). These cause occupational asthma and are subject to strict workplace exposure limits (WEL of 0.02 mg/m3). Gun-applied expanding foam is the most common source on general construction sites, but spray-applied PU insulation carries far higher exposure levels.

Contact adhesives (solvent-based) contain volatile organic compounds such as acetone, toluene, n-hexane, or methyl ethyl ketone. They produce heavy vapour that pools at floor level in poorly ventilated spaces. The flash point of many contact adhesives is below 0°C, making them a serious fire and explosion risk in confined areas.

Flooring adhesives vary widely. Pressure-sensitive adhesives are relatively low-risk. Solvent-based carpet adhesives carry VOC exposure hazards. Epoxy-based floor levelling compounds carry the full sensitisation risk described above. Always check the safety data sheet (SDS) rather than assuming a flooring adhesive is low-hazard.

Tile adhesives and sealants often contain silicone or MS polymer. Silicone sealants release acetic acid vapour during curing (the vinegar smell). Some rapid-set tile adhesives contain cement and can cause alkaline burns and chrome VI sensitisation. Epoxy grouts carry the same risks as other epoxy products.

Epoxy Resin: The Silent Career Ender

Epoxy resin deserves its own section because the consequences of poor control are severe and irreversible. Research consistently shows that 10 to 15 percent of workers regularly exposed to epoxy resins develop allergic contact dermatitis. The sensitising agent, bisphenol A diglycidyl ether (BADGE), penetrates skin rapidly and triggers an immune response that worsens with every subsequent exposure.

The problem is that there is no cure. Once sensitised, a worker will react to even trace contact with any epoxy product. For flooring installers, composite fabricators, waterproofers, and electricians who pot components in resin, this can mean the end of their career in that trade. Prevention is the only treatment.

Early signs include redness, itching, and small blisters on hands and forearms. Many workers dismiss these as general irritation and keep working, which accelerates full sensitisation. By the time they see a dermatologist, the allergy is established.

The amine hardeners in two-part epoxy systems are also hazardous. They are corrosive, causing chemical burns on contact, and are respiratory sensitisers. Mixing the two components generates heat and increases vapour release, so the highest-risk moment is during preparation and initial application.

Writing the COSHH Assessment

A COSHH assessment for adhesives must be product-specific. Using a generic assessment that says "adhesive" without specifying the type is not compliant. Follow these steps:

Step 1: Identify the Product and Its Hazards

Get the safety data sheet (SDS) for the exact product being used. Record the product name, manufacturer, and the specific hazardous substances it contains with their CAS numbers. Note the hazard statements (H-codes) from Section 2 of the SDS. For adhesives, pay particular attention to H317 (skin sensitiser), H334 (respiratory sensitiser), H225/H226 (flammable), and H336 (narcotic effects from solvent vapour).

Step 2: Assess Who Is Exposed and How

Consider all routes of exposure. Skin contact is the primary route for epoxy sensitisation. Inhalation is the primary route for isocyanates and solvent vapours. Record the duration and frequency of exposure, the quantities used, and whether the work is indoors or outdoors. Workers in adjacent areas may also be exposed to vapours and must be included in the assessment.

Step 3: Specify Control Measures by Adhesive Type

This is where most adhesive COSHH assessments fail. Generic PPE statements are not good enough. Here are the specific controls required for each type:

For epoxy resins:

Nitrile gloves are mandatory. Not latex (which causes its own sensitisation). Not vinyl (which epoxy penetrates within minutes). Nitrile, minimum 0.5mm thickness, chemical-resistant rated. Gloves must be changed every 15 to 20 minutes because breakthrough occurs faster than most people expect. Barrier cream alone is not sufficient for epoxy. It may supplement gloves but never replace them. Long sleeves and overalls must prevent any skin contact. Safety glasses or goggles protect against splashes. Adequate ventilation is needed during mixing and application.

For contact adhesives (solvent-based):

Forced ventilation in enclosed spaces. No hot works or ignition sources within the ventilated zone. Solvent-rated gloves (check the SDS for the specific solvent). Organic vapour respirator (A-type filter) if ventilation cannot keep exposure below the WEL. Air monitoring may be required for extended indoor use. Fire extinguisher on hand. Vapour is heavier than air and collects at floor level, so low-level extraction is more effective than high-level.

For PU adhesives and foams:

See the dedicated MDI section below. Disposable nitrile gloves are adequate for gun-applied foam. Spray-applied PU insulation requires full RPE, coveralls, and health surveillance.

Step 4: Health Surveillance

Health surveillance is legally required where workers are exposed to substances that cause occupational asthma (isocyanates) or dermatitis (epoxy resins). For isocyanate exposure, this means lung function testing before first exposure and at regular intervals. For epoxy workers, skin checks and symptom questionnaires should be conducted regularly. Any worker reporting skin irritation after epoxy contact should be removed from exposure immediately and referred to occupational health.

Step 5: Emergency Procedures

For skin contact with epoxy: remove contaminated clothing immediately, wash the affected area with soap and water (never solvent, which drives the chemical deeper into skin), and seek medical attention if irritation develops. For solvent inhalation: move to fresh air, keep warm and rested, seek medical attention if symptoms persist. For isocyanate inhalation: move to fresh air immediately, call emergency services if any breathing difficulty develops, and note that symptoms can be delayed by several hours.

Polyurethane Foam and MDI Exposure

Methylene diphenyl diisocyanate (MDI) is the isocyanate found in most construction PU products. It has a workplace exposure limit of 0.02 mg/m3 (8-hour TWA) and a short-term exposure limit (STEL) of 0.07 mg/m3. These are extremely low concentrations, which tells you how toxic this substance is.

MDI causes occupational asthma. Like epoxy sensitisation, once a worker develops isocyanate asthma, it is permanent. Continued exposure after onset leads to progressively worse attacks. HSE data shows isocyanates are consistently one of the top causes of occupational asthma reported through SWORD (Surveillance of Work-related and Occupational Respiratory Disease).

Gun-Applied PU Foam

Standard gun-applied expanding foam (the type used to fill gaps around window frames and pipe penetrations) releases relatively low levels of MDI because it cures quickly and the surface area exposed to air is small. For brief, well-ventilated applications, disposable nitrile gloves and natural ventilation are usually sufficient. However, when used in confined spaces, in large quantities, or for extended periods, the WEL can easily be exceeded. In those situations, forced ventilation and an A2P3 respirator are required.

Spray-Applied PU Insulation

Spray-applied polyurethane insulation is a completely different risk level. The product is atomised, creating a fine mist of unreacted isocyanate that is readily inhaled. MDI concentrations during spraying can exceed the WEL by 10 to 100 times. Workers applying spray foam must wear supplied-air respirators or powered air-purifying respirators (PAPR) with A2P3 filters, full coveralls with hood, and chemical-resistant gloves. No other workers should be in the building during application and for a minimum clearing period afterwards (typically 24 hours, but check the product SDS). Health surveillance with baseline and periodic spirometry is mandatory for all spray foam applicators.

A critical point for your COSHH assessment: MDI vapour concentration increases significantly with temperature. On hot days or when applying near heat sources, exposure levels rise sharply. Your assessment must account for seasonal and environmental temperature variation.

Generate Your COSHH Assessment

Writing a COSHH assessment for adhesives and resins means getting the product-specific details right. Generic templates that lump all adhesives together will not protect your workers or satisfy an HSE inspector.

SwiftRMS generates product-specific COSHH assessments that include the correct control measures, PPE specifications, and health surveillance requirements for the adhesive type you are using. Upload your safety data sheet or describe the task, and get a complete, printable COSHH assessment in minutes.

Related Guides

COSHH Regulations Explained provides a full breakdown of the Control of Substances Hazardous to Health Regulations, including employer duties and the hierarchy of control measures.

COSHH Assessment for Paint and Solvents covers solvent exposure in detail, including VOC monitoring and ventilation requirements that also apply to solvent-based contact adhesives.

COSHH Assessment for Silica Dust is relevant if your adhesive work involves cutting or grinding cured materials that contain crystalline silica, such as epoxy-bonded concrete or tile.