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March 4, 2019

North American Insulation Manufacturers Association voices concern on 7 eco-friendly insulation alternatives for a green home article


March 4, 2019

RE:      “7 eco-friendly insulation alternatives for a green home”

To Whom It May Concern:



The above-referenced article, “7 eco-friendly insulation alternatives for a green home,” has come to the attention of the North American Insulation Manufacturers Association (“NAIMA”).  NAIMA is the trade association for manufacturers of fiber glass and mineral wool insulation products.  NAIMA promotes energy efficiency and energy savings through the use of insulation products.  NAIMA also challenges deceptive and misleading claims about insulation products; it is in this context that this letter is written.

NAIMA’s letter will focus on specific erroneous statements about fiber glass insulation’s health and safety record and the inaccurate characterization of Icynene’s constituents, which your article states to be castor oil and water.  NAIMA is respectfully requesting that you consider the following facts as you may write additional articles on insulation.



Your article states that fiber glass insulation “can cause many health issues.”

Fiber glass insulation is safe to manufacture, fabricate, install and use when recommended safe work practices are followed.  Please consider the following facts about the health and safety record.

In October 2001, an international expert review by the International Agency for Research on Cancer (“IARC”) re-evaluated the 1988 IARC assessment of glass fibers and removed glass, rock and slag wool fibers from its list of substances “possibly carcinogenic to humans.”[1]  All fiber glass and rock and slag wools that are commonly used for thermal and acoustical insulation are now considered not classifiable as to carcinogenicity to humans (Group 3).  IARC noted specifically:

Epidemiologic studies published during the 15 years since the previous IARC Monographs review of these fibres in 1988 provide no evidence of increased risks of lung cancer or mesothelioma (cancer of the lining of the body cavities) from occupational exposures during manufacture of these materials, and inadequate evidence overall of any cancer risk.[2]

IARC based this decision on new and better data on fiber glass.  IARC also retained its Group 3 classification for continuous glass filaments and the Group 2B “possible carcinogen” classification for certain special purpose glass fibers.

In June 2011, the U.S. National Toxicology Program (“NTP”) removed from the Report on Carcinogens (“RoC”) biosoluble glass wool fibers used in home and building insulation.[3]  NTP stated that “not all glass wool fibers cause cancer.”[4]  In fact, the vast majority of glass fibers manufactured in the United States are not considered carcinogens by NTP.  Also, in 2011, California’s Office of Environmental Health Hazard Assessment (“OEHHA”) published a modification to its Proposition 65 listing to include on “Glass Wool Fibers (inhalable and biopersistent).[5]

The NTP and IARC decisions are consistent with the conclusions reached by Health Canada in 1993, the Agency for Toxic Substances and Disease Registry (“ATSDR”) in 2004, and the U.S. National Academy of Sciences, which in 2000 found “no significant association between fiber exposure and lung cancer or nonmalignant respiratory disease in the MVF [man-made vitreous fiber] manufacturing environment.”  These findings are further supported by one of the most comprehensive epidemiological studies ever created covering nearly a million person-years of exposure between 1945 and 1995.[6]



Icynene is a spray foam insulation product.  It is not made from castor oil and water.  All spray foam products have certain constituents in common.

A spray polyurethane foam product typically contains such ingredients as diisocyanates and polyols.  Moreover, exposure to isocyanates can cause permanent damage to the respiratory system such as skin sensitization and asthma; the asthma can be fatal.[7]  Exposure may occur via inhalation, ingestion, skin contact, and eye contact, which necessitates the use of complex respiratory and personal protective equipment.[8]  In addition, the installer is at risk because spray foam is highly flammable at the time of application.  During the installation process, applications that exceed the recommended thickness may cause spontaneous combustion of the foam.  In fact, deaths have resulted during installation when the spray foam ignited due to static electricity or other electric sources.[9]  The chemicals associated with spray foam are considered “hazardous chemicals” under the Occupational Safety and Health Administration’s (“OSHA”) Hazard Communication Standard, and waste from the drums used to create spray foam insulation is considered hazardous waste under the Resource Conservation and Recovery Act (“RCRA”).

These are not the characteristics that consumers would likely associate with a product claiming to be green.

NAIMA urges you to search Icynene’s website.  Even they do not claim to be made of castor oil and water.  Icynene has on its website links to its safety data sheets which fully discloses the toxic constituents that make up spray foam products.




NAIMA respectfully requests your consideration of the information set forth in this letter.  If you have any questions, please do not hesitate to contact me at 703-684-5670.


Angus E. Crane

Executive Vice President, General Counsel


[1] International Agency for Research on Cancer, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Man-Made Vitreous Fibres, Vol. 81 (Lyon, France: WHO/IARC, 2002).

[2] IARC Press Release, 24 October 2001 (

[3] U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program, Report on Carcinogens, Twelfth Edition, 2011 ( /roc12.pdf).

[4] National Institute of Environmental Health Sciences, National Toxicology Program, Fact Sheet, “The Report on Carcinogens,” June 2011 (

[5] Biosoluble glass wool fibers dissolve more rapidly in body fluids than other fibers that have been associated with human disease.

[6] Marsh GM, Buchanich JM & Youk AO (2001) Historical cohort study of U.S. man-made vitreous fiber production workers; VI. Respiratory system cancer standardized mortality ratios adjusted for the confounding effect of cigarette smoking. Journal of Occupational and Environmental Medicine 2001;43:803-808.  Marsh GM, Gula MJ, Youk AO, Buchanich JM, Churg A & Colby TV (2001) Historical cohort study of U.S. man-made vitreous fiber workers. II. Mortality from mesothelioma. Journal of Occupational and Environmental Medicine 2001;43:757-766.  Marsh GM, Youk AO, Stone RA, Buchanich JM, Gula MJ, Smith TJ, Churg A & Colby T (2002) Does fiber glass pose a respiratory system cancer risk in humans? Latest findings from the US cohort and nested case-control studies. Annals of Occupational Hygiene 2002;46 (Suppl 1):110-114.  Marsh GM, Youk AO, Stone RA, Buchanich JM, Gula MJ, Smith TJ & Quinn MM (2001) Historical cohort study of U.S. man-made vitreous fiber production workers. I. 1992 fiber glass cohort follow-up – Initial findings. Journal of Occupational and Environmental Medicine 2001; 43:741-756.

[7] National Institute for Occupational Safety and Health, Preventing Asthma and Death from Diisocyanate Exposure, NIOSH Alert: 1996, DHHS (NIOSH) Publication No. 96-111 (

[8] Ibid.

[9] Cape Cod Online, “Police identify victim of Saturday’s fatal fire,” May 19, 2008 (www.capecodonline).


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