NIOSH Programs > Respiratory Diseases > Evidence Package > 3. Interstitial Lung Diseases > 3.3 Fiber-Induced Diseases
3.3c) Reduce Occupational Exposure to Refractory Ceramic Fibers3.3b) Identification and Control of a Newly Recognized Occupational Lung Disease Affecting Flock Workers | 3.3d) Define Determinants of Fiber Toxicity
Manufactured RCFs are increasing as substitutes for asbestos in a myriad of industrial products and applications requiring lightweight, high-heat insulation (e.g. furnace and kiln insulation). Exposure to RCFs has been shown to cause mesothelioma and lung cancer in laboratory animals, and has been associated with pleural plaques, irritation of the skin, eyes, and respiratory tract, and reduced lung function in exposed workers. More than 31,000 workers in the U.S. are at risk of exposure to RCFs.
RDRP researchers have been studying the potential adverse health effects of airborne RCFs since the early 1980s. Our scientists have reviewed and summarized existing data relating to RCFs and recently developed and disseminated a NIOSH criteria document on RCFs to provide occupational safety and health guidance for employers and workers who manufacture, process, and handle RCFs and RCF products. Throughout the development of the criteria document, our researchers worked closely with their counterparts in industry, academia, organized labor, and other federal agencies in interpreting the available health data and identifying research gaps. Our scientists also collaborated with the RCF Coalition, an industry group, in conducting workplace engineering control studies to identify techniques that could reduce airborne fiber concentrations. We also organized and coordinated at least two public forums to review major toxicological, epidemiologic, exposure assessment, and control issues for the RCF industry.
In 1995, RDRP scientists began working with EPA in reviewing data from an EPA consent agreement with the Refractory Ceramic Fiber Coalition in which the industry agreed to collect RCF exposure data during the manufacture and use of RCF materials. The Refractory Ceramic Fiber Coalition entered into the agreement with EPA to collect exposure data in accordance with EPA's Significant New Use Rule. Our scientists helped verify the exposure measurements and provided input to EPA on the logistics of sample collection. The EPA required monitoring of exposure data with the intent to reduce exposures during manufacture and use of RCFs, given available evidence of carcinogenicity of RCFs from chronic inhalation studies in rodents.
When EPA transferred responsibilities for the ongoing monitoring of the RCF industry's efforts to reduce worker RCF exposures to OSHA in 2000, OSHA and RDRP scientists were invited by the Refractory Ceramic Fiber Coalition to assist in the development of a formal product stewardship program for RCFs. Our staff helped shape the final Product Stewardship Program, particularly in the areas of ongoing exposure monitoring, a medical surveillance program for exposed workers, and a recommended exposure guideline for RCFs of 0.5 fibers per cubic centimeter (f/cm3). The program specifies a series of performance measurements in the areas of work practices, worker training, medical monitoring, exposure monitoring, quality assurance/quality control, and customer service activities. For each area, various goals, measurements, and time-phased deliverables are specified.
Outputs and Transfer
RDRP scientists very recently completed a NIOSH criteria document on RCFs (NIOSH: “Criteria for a Recommended Standard: Occupational Exposure to Refractory Ceramic Fibers,” 2006, A3-85). This major science-based policy document describes occupational exposure to RCFs and recommendations for protecting workers. Even as a draft, released for external review prior to finalization, it has proved highly influential, helping to move the RCF industry towards a comprehensive worker health protection program and specifically the current exposure guideline for RCFs of 0.5 f/cm3 incorporated into the RCF Product Stewardship Program.
RDRP scientists developed and evaluated engineering controls to reduce exposures to during the sanding of RCF-containing materials. Worker exposures associated with sanding operations, which had earlier been shown by our researchers to generate some of the higher worker exposures to RCFs, were shown to be reduced by at least 50 percent by improving existing exhaust ventilation controls. This work was documented in the scientific literature (12, A3-108).
RDRP scientists organized and coordinated a roundtable session at the American Industrial Hygiene Conference and Exposition (2000) on the topic of manufactured synthetic fibers and their potential hazards. The roundtable was comprised of representatives from multiple fiber manufacturing industries, labor interests, academia, and OSHA, and proceedings entitled “Synthetic Fibers in the Workplace: Where Less is Healthier” (2001) have been published in book format by the American Industrial Hygiene Association (AIHA).
Interactions of RDRP scientists with external partners have helped stimulate the development of a Product Stewardship Program by the RCF Coalition from 2000 to 2002. Our scientists helped to shape the Product Stewardship Program, especially in the areas of ongoing exposure monitoring, a medical surveillance program for exposed workers, and an exposure guideline of 0.5 fcm3. The Product Stewardship Program, which includes recommendations for reducing workplace exposures to RCFs, was endorsed by OSHA as the basis for a voluntary OSHA standard and, in 2002, the Refractory Ceramic Fiber Coalition entered into a voluntary agreement with OSHA to abide by this Product Stewardship Program and to assist users of RCFs in the reduction of exposures. Our scientists participate with OSHA counterparts in an annual review of the industry's progress in implementing the Product Stewardship Program.
In 2004, the RCF Coalition asked RDRP scientists to assist with training needs, specifically in the use of the training intervention effectiveness research model. Our experts in training effectiveness research have responded to that request with visits to RCF Coalition member companies’ facilities to observe manufacturing processes prior to providing specific guidance on using the training intervention effectiveness research model.
Progress Towards End Outcomes
Over the time that RDRP scientists have collaborated with the RCF Coalition, mean fiber exposure concentrations in the RCF manufacturing industry have declined dramatically. A documented benefit of the reduced exposures has been an improvement of pulmonary function test results for workers who manufacture RCF. A long-term ongoing longitudinal epidemiologic study of workers in the RCF manufacturing industry, conducted by researchers at the University of Cincinnati, College of Medicine, has shown that initial decrements in pulmonary function for workers were related to higher exposures existing prior to significant reductions in airborne fiber concentrations characteristic of current conditions.94
To date, the RCF Coalition has met or exceeded all Product Stewardship Plan requirements, and continues to report its progress to RDRP scientists in an annual meeting hosted by OSHA.
RDRP scientists, together with those of other federal agencies, will continue to monitor progress of the Refractory Ceramic Fiber Coalition’s Product Stewardship Program and plan to participate in the annual briefing where a summary of progress will be reported.