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Exposure Potential

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Potential Chemical Exposures
Chemical exposures from SPF may occur through a variety of ways. The work site should be restricted to persons wearing appropriate personal protective equipment.

  • Vapors and Aerosols
    • Spray application generates isocyanate vapors and aerosols. 
    • Research data indicate that inhalation exposures during SPF insulation will typically exceed OSHA occupational exposure limits (OELs) and require skin, eye and respiratory protection.
    • Vapors and aerosols can migrate through the building if the area is not isolated and properly ventilated.
    • After application, vapors may linger in a building until properly ventilated and thoroughly cleaned.
  • Dust
    • Cutting or trimming the foam as it hardens (tack-free phase) may generate dust that may contain unreacted isocyanates and other chemicals.
    • After application, dust may linger in a building until properly ventilated and thoroughly cleaned.
  • Heat-generating processes
    • Any heat-generating processes such as drilling, welding, soldering, grinding, sawing, or sanding on or near the foam insulation may generate a range of airborne degradation (PDF) (3 pp, 109K) Exit EPA Disclaimer chemicals, including, isocyanates, amines, carbon dioxide, carbon monoxide, hydrogen cyanide, or nitrogen oxides.
  • Fires
    • Fires involving SPF may release isocyanates, hydrogen cyanide, amines, and other toxic chemicals into the air. Read Isocyanates (Emissions from fires) (PDF) (130 pp, 10 MB). Fire departments have issued advisories and require the use of full supplied air respirators when fighting polyurethane fires.

Curing
“Curing” of SPF means that the chemicals in the product are reacting to produce polyurethane foam. SPF material is highly adhesive and will stick to most surfaces. SPF may appear hardened or "tack-free" within a range of a few seconds to a few minutes after application.  However, at this stage, the foam is still curing and still contains unreacted SPF chemicals.

Some manufacturers estimate that it can take approximately 23-72 hours after application for the foam to fully cure for the two-component high pressure "professional" SPF system, and approximately 8 to 24 hours to cure for one component foam, typically available in 12 oz. to 24 oz. cans, but more research is needed to account for the potential variability of curing rates.

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Curing Rates of SPF Affect Re-Entry Times
The curing time (complete reaction) varies depending on the type of SPF product, product formulation, applicator technique, foam thickness, temperature, humidity and other factors, which will impact re-occupancy Exit EPA Disclaimertime. Cutting or trimming foam before it is fully cured may cause exposure to unreacted SPF chemicals.

Homeowners, school administrators, and other decision-makers should get clear guidance from contractors, system houses, and product manufacturers on the appropriate time of year to install SPF in your area or weather conditions that may impact the installation of SPF.  Temperature and humidity play a critical role in the curing of SPF ingredients. More product research is needed to understand the implications variability may play in future potential off-gassing.  Ask to see any reports developed from product testing on re-entry times and the impact of the variability of factors that influence curing.

The polyol blend (B-side) contains a variety of proprietary chemicals and curing rates may vary for different SPF product formulations. Read the manufacturer’s recommendation in the material safety data sheet (MSDS) and other product information for all types of SPF products and applications.

Air sampling and testing the indoor air following SPF installation is one way to assure the foam is completely cured. Emissions testing of SPF foam applied in a laboratory and in the field (at the work site) may vary. Testing should be conducted by a certified laboratory using a validated method such as the Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions from Indoor Sources Using Environmental Chambers, Version 1.1 (2010) (PDF) (52pp, 429KB) under California Section 01350 Exit EPA Disclaimer.

Long-term Concerns for Exposure Potential
After spray foam is applied and cured, it is considered to be relatively inert; however, there are several situations where the cured foam may pose additional potential risks.

  • Maintenance workers, including plumbers and electricians, should not heat or grind spray foam. Spray foam can potentially generate toxic emissions under these circumstances.
  • Building renovations, demolition, or building disassembly done years later can disturb spray foam insulation. Performing hot work on or near polyurethane foam may lead to potential exposures to isocyanates and other toxic emissions.

Potential Off-Gassing
The potential for off-gassing of volatile chemicals from spray polyurethane foam is not fully understood and is an area where more research is needed.

One method for measuring volatile chemicals is the standard method under California Section 01350. In addition, ASTM International, an organization that sets standards for products and materials, has initiated development of a standard (D22.05) to determine volatile organic compounds, diisocyanates, oligomeric isocyanates, and amine catalysts emitted from SPF insulation products designed for on-site application in buildings (ASTM WK30960). Exit EPA Disclaimer

Should I Take Action or Remove SPF That Has Been Installed?

If home or building occupants have concerns that they may be exposed to residual SPF chemicals, potential off-gassing, or continue to smell odors, consider the following:

  • Work with the contractor to identify the problem or consider hiring an independent expert such as a qualified Indoor Air Quality (IAQ) consultant to diagnose sources of indoor air issues.
  • If you experience breathing problems or other adverse health effects, seek immediate medical attention.
  • Contact the contractor and/or product manufacturer to request help in solving the problem if the SPF material is shown to be the source of the problem.
  • If concerns are not resolved with the contractor and/or product manufacturer, affected parties should contact their local or state consumer protection office or contractors’ licensing board.
  • EPA is not currently aware of standard accepted removal and/or remediation practices.  This is an area for further investigation and research as future renovation and deconstruction of buildings where SPF has been applied are anticipated.
  • Note: Removal may not resolve the problem and may create other problems.

When spray foam has been correctly applied and cured, it is usually considered to be relatively inert; however, there are factors that impact curing rates and some long-term concerns for exposure potential.

If SPF was not applied properly, chemical contaminants may have migrated to hard and/or soft surfaces elsewhere in the building and may be the source of residual odors; therefore, removal may not resolve the issue.  Also, disturbing SPF material might generate dust or hazardous materials if done improperly, especially if using processes that might heat (PDF) (3 pp 109K) these materials.

Before you renovate or have other activities done in your home or building, find out whether SPF is present and consider following the guidance on re-occupancy and other steps to control exposures, such as clean-up and ventilation practices.

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