Common Questions

About Refractory

Ceramic Fibers

"Common Questions About Refractory Ceramic Fibers" is published by the RCF Coalition, an association of the leading U. S. producers of refractory ceramic fibers (RCFs) -- Thermal Ceramics and Unifrax Corporation. The RCF Coalition develops and promotes proper work practices and standards for the industry, conducts health research and disseminates information on the proper handling and use of RCFs. This publication is designed to provide basic information about RCFs and the RCF industry.

What are refractory ceramic fibers (RCFs) and where are they used?

Refractory ceramic fibers (RCFs), along with fibrous glass and mineral wool, are part of a group of man-made materials generally referred to as synthetic vitreous fibers (SVF). All these products are made from molten masses of raw materials, under highly controlled conditions. RCFs make up the smallest portion of the SVF industry, accounting for less than one percent of total worldwide SVF production. RCFs are used primarily in industry as insulation for high-temperature applications such as furnaces, boilers and other heating equipment subjected to temperatures up to 2,800°F. RCFs also are used as insulation in the aerospace, automotive and appliance industries, and in fire protection. In these applications, they are contained or encapsulated within the products.

What are the benefits of RCFs?

RCFs play an important energy-efficiency role in the U. S. and other nations by reducing fuel consumption in industrial applications by as much as 25 to 50 percent. As a highly efficient insulation product used to control high temperatures, RCFs help minimize the use of scarce natural energy resources by reducing the consumption of fossil fuels.

RCFs help product quality by maintaining proper operating temperatures in furnaces, boilers and other hot equipment in industrial plants that process petroleum, steel, aluminum, glass and other products. RCFs also protect workers from exposure to the high temperatures generated by industrial heating equipment.

What is the current status of health research on RCFs?

Ongoing studies of the health of current and former workers in the RCF industry have found to date no clinically significant disease as a result of exposure to RCFs.

Results of inhalation tests with animals show that RCFs cause fibrosis and lung and pleural cancer when administered at very high doses (the so-called "maximum tolerated dose" for 6 hours/day, 5 days/week for 24 months).

In one European study, test animals (rats) were exposed for 24 months to varying levels of RCFs --3, 9 and 16 milligrams per cubic meter (mg/m3); 25, 75 and 115 fibers per cubic centimeter (f/cc), respectively -- in order to help determine a threshold exposure level at which disease does not occur. Exposure at these levels produced no statistically significant increase in the risk of tumor. However, a single mesothelioma was diagnosed in one of 116 rats in the 9 mg/m3 (75 f/cc) exposure group, and minimal fibrosis, another lung disease, was found in rats from the 9 and 16 mg/m3 groups (75 and 115 f/cc, respectively). No fibrosis was noted in the 3 mg/m3 (25 f/cc) group.

Other completed animal studies have indicated that RCFs are capable of causing cancer in test animals when surgically implanted into the animals' bodies.

Because of possible risk from exposure to RCFs and based on the animal study results to date, RCF producers believe it is necessary and appropriate to control the workplace environment, and to reduce worker exposures to the lowest possible level.

Many national and international regulatory bodies, including the U. S. Environmental Protection Agency (EPA) and the World Health Organization's International Agency for Research on Cancer (IARC), believe that substances that cause cancer in animals at very high doses may present a corresponding hazard to people. However, since people tend to be exposed to comparatively low doses, an increasing number of scientists believe that the human risk may be very different. Regardless, ceramic fibers have been classified by IARC in 2001 as 2(b) -- a possible human carcinogen, based on sufficient evidence of carcinogenicity in experimental animals, and inadequate evidence (no data) on the carcinogenicity of ceramic fibers to humans.

Is it important to follow manufacturers recommended handling guidelines?

Yes, manufacturers recommended work practices should be strictly adhered to. RCF producers believe that control of people's exposure to the lowest possible levels of RCFs is both necessary and appropriate given the scientific studies to date. Each RCF producer outlines its recommended work practices in documents called material safety data sheets (MSDS) as well as other company literature.

Why do RCF products carry warning labels?

RCF producers label their products to warn of potential hazards, as part of each company's commitment to keeping employees and customers informed and to help ensure that proper work practices are followed. Labels also are applied in compliance with federal and state regulations, such as the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard. As new regulations are announced or new results come in from research studies, these companies would then modify their labels appropriately.

Should workers actively seek to minimize RCF exposures?

Yes. As with many products used every day, measures to control or reduce exposures always should be taken. Properly designed and operated engineering controls are the most effective methods for minimizing airborne dust and fiber particulates to reduce risk. If exposures exceed the Recommended Exposure Guideline (REG) or are unknown, personal protective equipment must be used. For special recommendations, consult your RCF Coalition member's material safety data sheet (MSDS).

What steps has the RCF industry taken to protect workers in manufacturing sites as well as customers' workers?

The health of all workers in RCF Coalition manufacturing sites is medically monitored on an ongoing basis through a Pulmonary Medical Surveillance Program.

In addition, RCF Coalition members have comprehensive Product Stewardship Programs in place for their customers that consist of seven steps and many are designed to reduce worker exposure to the lowest possible level. The Product Stewardship Program consists of communications, workplace monitoring, evaluation of workplace controls, exposure assessments, health effects research, product research and special studies.

Each RCF Coalition member has its own comprehensive communications program to provide employees and customers with current information on proper handling practices for RCF products, health research and exposure guidelines.

Components of these communications programs include items such as material safety data sheets (MSDS), work practices guidelines, a health information kit, a video tape entitled "The Proper Handling and Use of Refractory Ceramic Fibers" and other specialized information. In addition, there is ongoing communication on methods for reducing workplace exposures. Call the product stewardship program representative at your RCF Coalition member manufacturer for the specifics of its communications program.

RCF Coalition members also can provide technical assistance to help customers evaluate workplace exposures.

Additionally, RCF Coalition members sponsor medical and scientific research to help determine any potential long-term health effects of inhalation exposure to RCFs, as well as conducting product research to develop new product forms that will help reduce risk from exposure. Finally, RCF Coalition members are involved with waste minimization and waste handling programs and are researching recycling programs to help ensure the proper handling and use of ceramic fiber materials.

This Product Stewardship Program is a thorough health and safety program. In addition, each RCF Coalition member outlines its recommended work practices in its MSDS documents as well as other company literature.

The Environmental Protection Agency (EPA) has acknowledged the RCF industry's support for worker health and safety, and noted that the industry has voluntarily conducted scientific research and promptly supplied research results to EPA and other agencies.

How does the RCF industry work with federal health officials?

RCF Coalition members have always cooperated fully and voluntarily with federal agencies, furnishing them with all health and safety studies completed or now in progress, as well as documents and information that detail how RCFs are made, used and installed and how workers are protected from exposure.

During the last several years, RCF Coalition members have met on numerous occasions with EPA officials, as well as federal officials from OSHA -- which has the authority to set workplace exposure limits for RCFs -- and the U. S. National Institute for Occupational Safety and Health (NIOSH) -- which has an advisory and technical role.

RCF Coalition members will continue to work voluntarily with EPA and other agencies to ensure that the health and safety of workers and customers are protected.

Is the general public exposed to RCFs?

Because RCFs are primarily used in industrial settings, exposure to the general public is minimal. While RCFs are used in the manufacture of some consumer products, such as automotive brake pads, hearth products, fire protection and self-cleaning ovens, the insulation is enclosed, encapsulated or bound within the product.

Where can I get more information?

For more information, contact the RCF Coalition or a member company:

For more information, contact RCFC or a member company:

Thermal Ceramics (http://www.thermalceramics.com)
(800-722-5681)

Unifrax Corporation (http://www.unifrax.com)
(800-322-2293)

RCF Coalition members are dedicated to researching the health and safety effects of RCFs, educating workers and customers on proper handling procedures and disseminating the preliminary and final results of research studies.