Decades of Monitoring Demonstrate Exposure Remains Low

Dec 14, 2021 9:06:40 AM By Stacy Fitzgerald-Redd
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KeysToSuccess_1The North American Insulation Manufacturers Association (“NAIMA”) is the association for North American manufacturers of fiber glass and mineral wool insulation (including rock wool and rock and slag wool) products. NAIMA’s role is to promote energy efficiency and environmental preservation through the use of fiber glass, rock wool, and slag wool insulation and to encourage the safe production and use of these materials.


A significant development in promoting occupational safety and hygiene for fiber glass and rock and slag wool insulation occurred in 1999 when the fibrous insulation industry, led by NAMA and the Occupational Safety and Health Administration (“OSHA”), agreed on a voluntary and comprehensive worker safety program called the Health and Safety Partnership Program (“HSPP”). The HSPP had a three-year ramp-up period through 2002, followed by five years of full implementation through 2007. When the HSPP was successfully completed, NAIMA and its member companies opted in 2008 to continue all components of the HSPP voluntarily as the NAIMA Product Stewardship Program. This program has continued through the present day.


The HSPP had a number of worker protection elements, including setting a voluntary permissible exposure limit (“PEL”) of one fiber-per-cubic-centimeter (“1 f/cc”) as a time-weighted average (“TWA”) over an eight-hour shift, along with a series of recommendations on product design, engineering controls, work practices, recommended guidelines on the use of respiratory protection, or a combination of the above to achieve the 1 f/cc exposure limit. To promote these best practices, NAIMA distributes work practice facts sheets and other training materials.


A key component of the HSPP was NAIMA’s commitment to create, maintain, and update an occupational exposure database for workers installing, fabricating, or handling fiber glass and rock and slag wool insulation products. The database provides averages and ranges of exposure for a variety of fiber types, workplace settings, job tasks, and product types. Contractors or worker representatives can rely on the aggregated exposure data to ascertain exposure levels of specific combinations of fiber types, insulation applications, job locations, and product types. This information and data can then inform the respiratory protection and work practice recommendations of the HSPP and applicable OSHA respiratory program requirements.


OSHA has endorsed this reliance on industry-wide databases in its Respiratory Protection Standard preamble by specifically referring to NAIMA’s exposure database. Insulation contractors that utilize the findings from the HSPP exposure database can therefore avoid the expense and time of conducting their own exposure testing for purposes of complying with industry standards and the OSHA Respiratory Protection requirements.


The database was populated by collecting data from historical company exposure monitoring programs, previously published fiber exposure studies, ongoing industrial hygiene programs by NAIMA’s member companies, and by targeted NAIMA-funded exposure monitoring surveys of special installation and fabrication activities. All exposure data points entered into the database were required to provide specific data elements and were reviewed and approved by a quality assurance committee composed primarily of industrial hygienists.


The first summary of the HSPP exposure database was published in 2002. At that time the database contained the results of approximately 6,000 samples. The conclusion of the summary was that exposures across the board were low. In fact, the samples showed that exposures were consistently well below the recommended 1 f/cc.


An updated analysis was published in 2009 based on data collected up to the end of 2007. At the time of the 2009 update, the database contained 14,280 samples. NAIMA and its member companies, both large and small manufacturing companies which are all involved in the manufacture of fibrous insulation, have continued to maintain and update the exposure database as part of the NAIMA Product Stewardship Program, the follow-on to the HSPP. NAIMA provides contractors, fabricators, and others a detailed summary of the database and responds to specific questions about exposures. The conclusion of the 2009 update was, again, that exposures were low and still consistently well below the recommended 1 f/cc.


Although glass wool has been produced and used for more than a century, recent market, regulatory and process changes have resulted in major changes in the glass wool and mineral wool manufacturing industry. One change is that the demand for insulation products has increased in recent years due to a growing awareness of the benefits of insulation in conserving energy consumption and reducing greenhouse gas emissions. Insulation has been shown by the Harvard School of Public Health to be the most cost-effective means of improving energy efficiency in buildings and reducing greenhouse gas emissions. An updated study by Boston University in 2016 calculated the energy savings from increased insulation use in all homes would result in annual reductions of 80 million tons of CO2, 68,000 tons of NOx, and 120,000 tons of SO2. These significant energy consumption savings and climate change benefits create incentives for building owners and builders to increase the use of insulation in existing and new buildings. The resulting increased demand for insulation products could potentially affect manufacturing worker exposures, both from bringing online new manufacturing capacity and increases in the number of workers employed on existing production lines.


A second change surrounded the 2001 delisting of fiber glass and mineral wool insulation products as a possible carcinogen by the International Agency for Research on Cancer. Similar removal of fiber glass as possible carcinogens by the U.S. National Toxicology Program’s Report on Carcinogens and California’s Proposition 65 list in 2011 altered the specter of a health concern in the United States. These actions meant that, after 2011, glass fiber and mineral wool fiber insulation products no longer needed to warn for any potential cancer hazard.


Third, significant process changes in the glass wool manufacturing industry include the substitution of formaldehyde binders with formaldehyde-free binders that are starch/sugar- or acrylic-based as a compliance strategy for the Wool Fiberglass MACT Standard promulgated by the U.S. Environmental Protection Agency (“EPA”) in 1999 under the Clean Air Act. The most significant process change from this Standard was the voluntary substitution of phenol formaldehyde binders with non-phenolic formaldehyde binders; formaldehyde was the chief hazardous air pollutant (“HAP”) regulated by the Wool Fiberglass MACT Standard. EPA found in proposing to update the rule in 2011 that these actions substantially reduced hazardous air pollution emissions in and from fiber glass facilities by 95%. While these process changes have reduced worker and environmental exposures and risks from hazardous air pollutants, the impact on manufacturing worker glass fiber exposures (if any) had not previously been evaluated.


There was an expression of concern that the removal from cancer warning lists, increased production, and new binder might give license to increase exposures. Therefore, a third summary of the exposure database was published in 2021. The database contained results of 17,718 samples. Although significant regulatory and process changes have occurred in the glass wool manufacturing industry over the past decade, these changes have not resulted in any major changes in glass wool primary manufacturing exposures, which still remain well below the 1 f/cc voluntary PEL. The results further demonstrate that worker exposures across the various job functions in the glass wool manufacturing sector have generally not significantly increased as a result of recent process and regulatory changes in this industry.




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