Beginning in the mid 1970s, individuals within the regulated community, and even within the federal government, began advocating the use of negotiated rulemaking as a more efficient, sensible alternative to the traditional “notice and comment” procedures typically followed by federal agencies in the development of regulations. In the 1980s, the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) began using a negotiated process as an aid to the development of certain regulations. By 1990, Congress formally endorsed negotiated rulemaking with the passage of the federal Negotiated Rulemaking Act, under the strong support of the Clinton Administration. Advocates of negotiated rulemaking tend to identify two primary benefits: reduced time to final rulemaking and a decrease in litigation over pending regulations. It is in this context that leading U.S. manufacturers in the refractory ceramic fiber (RCF) industry formed the Refractory Ceramic Fibers Coalition (RCFC), focused on workplace exposures to airborne fiber.

Background

Before discussing the RCF industry’s voluntary workplace protection program, it is useful to provide some background on the industry and the health issues associated with workplace exposure to RCFs. RCFs are advanced fibrous insulation materials used in various industrial, automotive, aerospace, and military applications requiring low weight and high heat resistance. RCFs are members of a group of materials commonly referred to as synthetic vitreous fibers (SVFs), a family of products that includes fiberglass (home insulation), rock wool, slag wool, and specialty high-temperature industrial fibers. RCFs are produced by melting and fiberizing a mixture of alumina (Al203) and silica (Si203). The combination of low density, low volumetric heat capacity and low thermal conductivity make this a valuable insulating material, particularly for high-temperature industrial applications. Invented in the 1940s, RCF sales grew substantially in the 1970s during the energy crises. RCFs now account for approximately one to two percent of the total SVF market in the United States.

RCFs contain individual fibers having a length weighted geometric mean diameter of less than 3 mm (respirable to humans); therefore, there is a potential risk associated with workplace exposures to airborne fibers. In the early 1990s, laboratory studies indicated that RCFs could cause cancer in animals exposed at doses hundreds of times higher than current average occupational workplace exposures. These studies are subject to extensive scientific debate, due to evidence of flaws in the study design. In contrast to animal studies, epidemiological investigations of persons actually exposed to RCF in the workplace for long periods of time did not show significant adverse health effects associated with RCF exposure. Nevertheless, the animal studies suggested that exposure to extremely high levels of RCF may pose some risk; therefore, RCF producers decided to take action to manage the potential human health risks and not to wait for more definitive scientific results or regulatory action.

Product Stewardship

The RCFC was formed in the late 1980s. The coalition and its member companies (Thermal Ceramics, Unifrax Corporation, and Vesuvius USA) account for more than ninety-five percent of all RCF currently produced in the United States. In 1991, the RCFC implemented a comprehensive, multifaceted Product Stewardship Program (PSP), designed to assist RCF manufacturers and end users in the evaluation, control, and reduction of workplace exposures to airborne fiber. The RCF PSP encompasses the entire “cradle-to-grave” life cycle of RCF-containing products, from primary manufacture, processing, and use through the ultimate disposal of RCF-containing materials.

The objective of the PSP for RCF was to help employees better manage the risk associated with workplace exposure to airborne RCFs. The PSP established and communicated proper material handling practices, engineering control technologies, personal protective equipment recommendations, regulatory information, and information pertaining to workplace exposure assessments. The PSP for RCF consists of the following seven key elements:

Health effects research:

This element includes epidemiological studies on worker cohorts, animal studies, and studies designed to learn more about fiber dosimetry—the relationships between exposure concentration, deposition in the deep lung, clearance of retained fibers, and possible biological effects. The information gained as part of this research is useful in conducting quantitative risk analyses.

Exposure assessments:

This element encompasses studies designed to estimate the exposed cohort (approximately 30,000 workers in the United States, and the same number in Europe) and to assess (qualitatively or semi-quantitatively) possible life-cycle exposure to various RCF-containing products. Based on this exposure “screening” analysis, products or product applications are identified and flagged for further quantitative analysis and executive review. The objective is to evaluate potential control options and, if these appear unsatisfactory, product substitutes.

Study of workplace controls:

This element (in concert with workplace monitoring) includes studies designed to identify and evaluate ways to reduce exposure (including engineering controls, workplace practices, and, for some jobs, use of personal protective equipment). Controls evaluated as part of this program element included use of general and local exhaust ventilation (LEV), baghouses, humidity control, isolation of high-exposure jobs, reengineering of dusty jobs, and development of improved work practices.

Workplace monitoring:

This element involves monitoring of task length average (TLA) and time-weighted average (TWA) fiber concentrations at facilities operated by RCF producers (termed “internal samples”) and their customers (termed “external samples”). The objectives are to identify high-exposure jobs, characterize exposure by industrial segment, detect time trends in occupational exposure, and use this information for benchmarking purposes. The study of workplace controls and workplace monitoring enabled the industry to examine the feasibility of meeting various occupational exposure limits (OELs). The industry adopted a series of progressively more stringent recommended exposure guidelines (REGs) based on monitoring results and demonstrated feasibility.

Product research:

This element includes reach initiatives designed to find ways to reduce potential exposure through product design (e.g., encapsulation), fiber dimension, and the development of high-temperature fibers that are less biopersistent.

Special studies:

This catchall category covers relevant projects that did not fit neatly into the elements listed above. Included in this category were studies to measure stack emissions, possible substitutes, and waste generation rates. Among other things, these studies were designed to anticipate regulatory needs and provide relevant information to decision makers.

Communications:

This element includes the use of various media to communicate the results of the PSP to employees, customers, unions, and government regulators. The industry developed videotapes, comic books (written in various languages), consumer telephone “hot lines” to provide time-critical information, material safety data sheets (MSDS), and (later) information posted on Internet sites maintained by the RCF producers, RCFC, and the European Ceramic Fibres Industry Association (ECFIA). A key part of the communications program was a customer outreach program. RCF producers helped form user groups (e.g., the RCF Vacuum Formers Association) to share relevant stewardship information. Another key component of the communications program was the decision to publish all scientific information in the peer-reviewed literature.

PSP 2002—Workplace Monitoring

On February 11, 2002, the RCFC member companies entered into a voluntary workplace protection agreement with OSHA. This program, entitled PSP 2002, is a highly acclaimed, multi-faceted strategic risk management initiative designed specifically to reduce workplace exposures to airborne RCFs. PSP 2002 has been developed for use wherever RCF is manufactured, fabricated, installed, or removed, as well as in other occupational settings where workers have potential exposure to airborne RCF. RCFC reports its progress on the implementation of PSP 2002 to OSHA annually. Although there are no reporting provisions for non-RCFC member companies, all RCF users were encouraged to adopt the key elements of PSP 2002. OSHA made a special point to commend RCFC for its commitment to assisting its industrial customers with managing workplace exposures to RCF. In a letter to RCFC dated February 11, 2002, the assistant secretary of labor for occupational safety and health, John Henshaw, commented, “OSHA believes that the commitment RCFC has made in developing the Program form an important step towards further improving worker protection. The 0.5 fiber/cc exposure guideline recommended in the Program, the specific engineering controls and work practices detailed in the Program, and the recognition that respiratory protection is appropriate in certain operations, will help reduce exposures of the workers who handle RCF products daily.”

Workplace industrial hygiene sampling is conducted using a stratified random sampling plan (SRSP) with stated data quality objectives (DQO). The purposes are to: 1) identify differences in workplace exposures among workers in different functional job categories (FJCs), 2) track time trends in average workplace concentrations, 3) learn if there are systematic differences between exposures of workers employed in identical FJCs by RCF producers compared to those employed by customers, 4) develop “before and after” snapshots to evaluate the effectiveness of intervention and monitoring, and 5) investigate whether there are systematic differences among customers in different industrial sectors. Because one major purpose of these samples is to track exposure changes over time, the data are referred to as historical baseline samples. All industrial hygiene workplace exposure monitoring for RCF is performed by industrial hygienists employed by RCFC member companies following the strict protocol outlined within a Quality Assurance Project Plan (QAPP). Sample collection and laboratory analysis is performed following the National Institute of Occupational Safety and Health (NIOSH) Method 7400 (NIOSH, 1989).

In addition to samples included as part of the SRSP, other samples, termed special emphasis samples (SES), are collected. These include personal monitoring samples, area samples, use of various analytical techniques (e.g., transmission electron microscopy, phase contrast microscopy, scanning electron microscopy) or Tyndall beam technology designed to better understand emission points and design engineered controls (dust collection). Special emphasis sample data are not pooled with historical baseline sample data for developing exposure estimates.

In 2005, RCFC member companies met all deliverables identified under PSP 2002. RCF workplace concentrations decreased in customer facilities by 28.5 percent, while remaining approximately the same (up four percent) for RCF manufacturers. The numbers of samples collected in 2005 actually exceeded the goals of PSP 2002 in each corresponding category, with overages of four percent for internal samples, sixteen percent for external “customer” samples, and thirty-six percent for special emphasis samples. Overall, weighted average airborne fiber concentrations have decreased substantially since 1990 (the inception of PSP for RCF).

In summary, 2005 was another successful year for PSP 2002 as all deliverables were provided and weighted average exposures remained approximately the same for RCF producers or decreased for customers. Looking ahead as the PSP 2002 program enters its fifth and final year, the RCFC is in the process of preparing a proposal for OSHA, NIOSH, and the EPA for the continuation of PSP for RCF. The industry intends to continue the PSP and look for ways to enhance its impact on reducing workplace exposures to airborne fiber.

Conclusion

Product stewardship for RCF has a 15-year proven track record of success. This comprehensive risk management strategy has given birth to new control technologies, modified handling practices, new fiber chemistries, a better understanding of workplace exposures to airborne fiber, and scientific discoveries that advance our understanding of the potential biological impacts of fiber exposure. Certainly, PSP for RCF can best be described as a work in progress, as future developments help us understand how to minimize the potential risks associated with workplace exposures to airborne RCF.