Workplace Exposure to Polybrominated Diphenyl Ethers (PBDEs)

Summary

PBDEs are chemical flame retardants used in plastics, upholstery fabrics, and foams in products such as computers, televisions, furniture, and carpet pads. PBDEs are showing up in the environment, in foods, in household dust, and in workplaces. In North America, PBDEs are being found at increasing levels in human blood, fat and breast milk. Current PBDE exposures have not been linked to health problems in workers or the general public, but scientists are concerned about the rapidly increasing PBDE levels in humans and the environment.

The most toxic PBDEs are no longer used in the manufacture of new products. However, workers may be exposed during disposal, dismantling, and recycling of plastic and foam products.

In workplaces where dust is generated when dismantling and shredding foams and plastics, exposure to PBDE occurs by breathing in dust and ingesting dust while eating, drinking , smoking, or other hand-to-mouth contact. Family members may also be exposed if workers wear dust-covered clothes home at the end of the work day. Employers and workers should take the precautions shown below to minimize their exposure to PBDEs.

What are PBDEs?

PBDEs are members of a broad class of bromine-containing chemicals used as flame retardants. They are often added to plastics, upholstery fabrics, and foams in products such as computers, televisions, furniture, and carpet pads. Historically, three types of PBDE were used in consumer products: Penta-BDE, Octa-BDE, and Deca-BDE. Each type of PBDE has different properties and uses.

The manufacturers of the most toxic PBDEs – Penta-BDE and Octa-BDE – voluntarily stopped production at the end of 2004. Consequently, Deca-BDE is the only PBDE flame retardant currently used in manufacturing.

What is the concern about PBDEs?

In recent years PBDE flame retardants have been found in the environment, in foods, in household dust, and in human tissue. In North America, PBDEs are being found at steadily increasing levels in human blood, fat, and breast milk. The highest levels of PBDEs in humans have been found in Canada and the United States, which are the largest consumers of the Penta- and Octa-BDE products, whose components are the most bioaccumulative of the PBDEs.

Since Penta-BDE and Octa-BDE are no longer used in new products, worker exposures to these more toxic PBDEs during manufacturing of foams and plastics should no longer be a concern. However, workers may be exposed to these PBDEs during disposal, dismantling, and recycling of plastic and foam products. A Swedish study showed that workers who dismantled electronics equipment and shredded plastic components at a recycling plant were exposed to PBDEs.

There is also evidence to suggest that computer technicians who repair electronic equipment are exposed to PBDEs in dust, but at levels much lower than those seen in plastics recycling. No studies of workers in the foam or furniture industries have been conducted, where Penta-BDE was primarily used.

Deca-BDE is currently the only PBDE product in production and is used in the following applications:

• Thermoplastic, elastomeric, and thermoset polymer systems, including:
  • high impact polystyrene (HIPS),
  • polybutylene terephthalate (PBT),
  • nylon,
  • polypropylene,
  • low-density polyethene (LDPE),
  • ethylene-propylene-diene rubber and ethylene-propylene terpolymer (EPDM),
  • unsaturated polyester,
  • epoxy
• Wire and cable insulation.
• Coatings and adhesive systems, including back-coatings for fabrics.

Examples of end products that use Deca-BDE include housings for televisions, aircraft components, computers, stereos, and other electronics, audiotape cassettes, and upholstery textiles.

Another Swedish study showed Deca-BDE exposure in two groups of workers. The first group produced rubber that was flame-retarded with Deca-BDE. The second group manufactured electric cables using flame-retarded rubber. Clearly, workers in many industries are potentially exposed to Deca-BDE.

It is important to note that we do not have any evidence that current levels of PBDE exposure are responsible for health problems in workers or the general public. However, scientists are concerned about the rapidly increasing levels of PBDEs in humans and the environment. Of most concern is the potential for damage to the developing fetus, resulting from the mother’s exposure to PBDEs during or prior to pregnancy. Although infants can be exposed to PBDEs through breast milk, the protective factors and health benefits that babies receive from breast milk are numerous. Consequently, breastfeeding is still considered the healthiest option for feeding babies.

Although Deca-BDE is generally regarded as being less toxic and less able to bioaccumulate than Penta-BDE and Octa-BDE, some scientists are concerned about the increasing use of Deca-BDE as a flame retardant and the potential for this material to be converted to more toxic PBDEs. The potential for Deca-BDE to be converted to more toxic and bioaccumulative forms, either in the environment or in human tissue, is the subject of much scientific debate.

What can I do to minimize exposure to PBDEs?

It is prudent to minimize exposure to PBDEs, particularly in workplaces where foams and plastics are dismantled and shredded. It is also important to realize that breathing in PBDE-containing dust is only one way that PBDEs can enter the body while at work. Workers may also ingest PBDEs if they don’t wash their hands before eating, drinking or smoking. It is unclear whether PBDEs can travel across the skin and into the bloodstream. Workers may also take the PBDE-containing dust home with them on their work clothes and expose their families.

The following recommendations for minimizing PBDE exposure in the workplace apply to both employers and workers:

• Employers should provide exhaust ventilation for plastic shredders and other equipment to remove PBDE-containing dusts from the air. The system must be carefully designed to ensure that it will adequately capture dusts and must be cleaned and serviced periodically to ensure optimal ventilation efficiency.
• Workers concerned about exposure to PBDE-containing dust may request the use of a respirator. An N95 dust mask will provide adequate protection; in this case the respirator use would fall under the provisions for voluntary use in Chapter 296-842 of the Washington Administrative Code (WAC), Respirators.
• Avoid stirring up PBDE-containing dust with dry sweeping or blowing. Wet cleaning and vacuuming with a HEPA-equipped vacuum cleaner are generally more effective.
• Eat, drink and smoke only in areas free of dust. Ensure that the break room remains clean. Wash down the tables and microwaves regularly.
• Use separate work clothes and shoes/boots while at work. Disposable coveralls are the best choice!
• Keep street clothes in a clean place.
• If possible, shower at work before going home. At the very least, wash your hands, arms, and face with soap and water. Be sure to use a clean towel.
• Don’t wear work clothes and shoes/boots home, unless PBDE-containing dust has been thoroughly removed from them. Preferably, work clothes should be laundered at work. Avoid taking PBDE-contaminated materials home, where the dust can come in contact with your family! If you must take work clothes home, wash and dry them separately.

The Washington State Department of Health provides some useful information about reducing exposure to PBDEs. While these guidelines are directed towards the general public, many of the suggestions also apply to the workplace.

Regulation & Policy

There are no legally enforceable occupational exposure limits for PBDEs. The American Conference of Industrial Hygienists (ACGIH) has developed a Workplace Environmental Exposure Level (WEEL) of 5 milligrams per cubic meter (mg/m3) for Deca-BDE. To date, no limits have been developed specifically for Penta-BDE or Octa-BDE. However, air monitoring would be required if dust levels could exceed 5 mg/m3.

How can I tell whether PBDEs are a concern in my workplace?

There may be a concern for PBDE exposures if your workplace generates dust when manufacturing products containing PBDEs or disposes or recycles plastic or foam. Employers may contact a regional WISHA consultant to obtain assistance. WISHA also investigates complaints from workers - call 1-800-4-BE-SAFE (423-7233).

Where can I find more information about PBDEs?

• The Department of Ecology’s Web site contains useful information about PBDEs, including current activities in Washington State.
• The Department of Health provides useful information about PBDEs and health.