When you’re thinking about any product for your home, health and safety are obviously a priority—and insulation is no different. When it comes to health and safety properties, not all types of insulation are equal.

Fire safety

Flame resistance is, naturally, a primary consideration for insulation in the home.

Some factors to consider when comparing insulation types for fire safety:

  • Fiberglass and mineral wool insulation
    Materials are noncombustible, and remain so for the life of the product. They require no additional fire-retardant chemical treatments—in fact, unfaced fiberglass and mineral wool are accepted as a fire block in wood frames. Note that some fiberglass and mineral wool facings (kraft paper, foil) are combustible, but when properly installed with a code-approved barrier, don’t pose a fire hazard. Kraft facing should never be left exposed.
  • Cellulose insulation
    Products are largely made of newspaper, which is highly combustible. Even though it’s heavily treated with fire-retardant chemicals prior to installation, it is a recognized fire hazard by the Consumer Product Safety Commission (CPSC).1
  • Spray Foam insulation
    Spray foam insulation will ignite at 700°F.2

Health Impacts

Not all insulation materials have undergone the same level of testing and scrutiny when it comes to health and safety.

  • Fiberglass and Mineral Wool insulation
    Fiberglass and mineral wool insulation are the most thoroughly tested insulation material available. The International Agency of Research on Cancer (IARC), the US National Toxicology Program (NTP) and the California Office of Environmental Health Hazard and Assessment have all stated that fiberglass and mineral wool thermal and acoustic insulations are not considered classified as carcinogens.
  • Cellulose insulation
    Questions about the health and safety aspects of cellulose insulation persist in the building industry because very little medical or scientific testing of the products has been conducted. There’s still a need for full toxicological testing of dust from cellulose building insulation and dust from pure cellulose fibers.3 Safety conclusions can’t really be drawn until extensive testing is completed.
  • Spray foam
    The safety of spray foam insulation is still being evaluated. If you’re worried about the impact of chemicals on your home and family, you’ll want to learn more about the chemical components of spray foam. According to the California Department of Toxic Substance Control, one of the main ingredients in spray foam, methylene diphenyl diisocyanate, could pose a number of health risks, including lung damage and asthma.

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Methylene diphenyl diisocyanate is known to damage lungs, cause asthma, and trigger asthma attacks in workers who install foam, per to the California Department of Toxic Substances Control. The US EPA has made comparable statements, detailed here.

Different spray foam manufacturers publish different guidelines for length of evacuation times during installation and curing. Note that there are no established evacuation timelines from any government agency.


Mold can grow in any environment where there’s moisture and food for mold spores, so many organic materials can be food for mold. Even though some products claim to be mold-resistant, mold can grow on ANY surface under moist conditions if organic material exists to support the spores. Some considerations when insulating to avoid mold:

  • Fiberglass, mineral wool, and spray foam insulation are all inorganic, and therefore don’t feed mold growth.
  • Cellulose insulation is composed of organic material, so it can be a food source for mold unless properly treated with chemicals or other agents that can prevent or inhibit mold growth. Mold can grow on all insulation types, but not all insulation products provide a food source for mold growth.


Risk of corrosion to pipes, wires and fasteners is a factor to consider at all phases of home building or improvement, and insulation is no exception.Your insulation choices can affect the possibility of corrosion:

  • Fiberglass insulation is not corrosive and contains no chemicals that can corrode pipes and wires4
  • Cellulose insulation contains certain chemicals routinely applied as a fire retardant to some cellulose insulation. These chemicals, particularly the sulfates, can cause the corrosion of pipes, wires, and fasteners under some conditions.5



  1. www.gpo.gov/fdsys/pkg/CFR-2009-title16-vol2/pdf/CFR-2009-title16-vol2-sec1404-4.pdf
  2. Thermal Barriers for the Spray Foam Industry, SPFA (2000)
  3. J.M.G. Davis, “The need for standardized testing procedures for all products capable of liberating respirable fibers; the example of materials based on cellulose,” British Journal of Industrial Medicine 1993: 50: 187-190, p. 189.
  4. X K. Sheppard, R. Weil, and A. Desjarlais, “Corrosiveness of Residential Thermal Insulation Materials Under Simulated Service Conditions,” Insulation Materials, Testing and Applications, D.L. McElroy and J.F. Kimpflen, Eds. (ASTM: Philadelphia, PA, 1990), pp. 634-654; K. Sheppard, R. Weil, and A. Desjarlais, “Corrosiveness Testing of Thermal Insulation Materials – A Simulated Field Exposure Study Using a Test Wall,” Report ORNL/Sub. 78-7556/4, September 1988.
  5. Donald W. Belles and Associates, Inc., “Loose-Fill Cellulose Insulation – An Aging Problem,” J. Applied Fire Science, Vol. 30, 295-303, 1993-94; Mark McLees, “‘Going Green’ May Make You ‘See Red,’” Firehouse, June 2008.