Flat Panel Displays (FPD) in electronic products such as televisions and computer monitors have quickly grown in popularity. The most common FPDs are liquid crystal displays (LCD) and plasma displays. By 2008, devices that contain FPDs are projected to account for nearly 85 percent of the total U.S. demand for electronic products. By 2013, the demand is predicted to reach 94 percent.
While relatively few FPD devices have entered the waste stream so far, they represent a potentially large volume of material that will be recycled or discarded in the future. Because of this, we need to fully evaluate how to manage these materials and determine if there are any potential risks associated with the end-of-life handling of these products.
Taking a proactive approach to this issue, the King County Solid Waste Division in Washington State has conducted the first known comprehensive review of information regarding the end-of-life management issues associated with FPDs. The goal was to identify and quantify potential chemicals of concern, evaluate hazards associated with these chemicals and assess potential risks from recycling electronic products containing FPDs. The results are reported in “Flat Panel Displays: End of Life Management Report,” which was published earlier this year. The report serves as a resource for a broad group of players — from local governments to e-waste processors — who are determining how to manage products that contain FPDs.
The report includes available information on the various chemicals used in FPD devices. Researchers found a considerable amount of data about the use and toxicity of chemicals of potential concern, including heavy metals like lead, mercury, cadmium and chromium, as well as brominated flame-retardants. Some uncertainty remains, however, about the full spectrum of potentially hazardous FPD constituents and the toxicity of some components, such as liquid crystals. Moreover, no studies have specifically addressed the potential exposure risks to recycling workers and communities near electronics recycling facilities.
LCDs are the dominant technology used in FPD devices. An LCD is made up of a number of pixels arrayed in front of a light source or reflector. Approximately 300 different liquid crystal compounds are available for use in LCDs. Depending on its specific performance attributes, a typical LCD can contain as many as 25 different liquid crystal substances.
Manufacturers of liquid crystals have run several batteries of toxicity tests of individual liquid crystals and a variety of mixtures. Findings to date suggest low acute toxicity, minimal skin/eye irritant effects, low potential for cancer effects based largely on mutagenicity tests, as well as low bioaccumulation potential and aquatic toxicity. For proprietary reasons, much of the supporting scientific data behind these conclusions were not available for review but reportedly meet or exceed European Union and Japanese criteria for hazardous material production and handling.
While available data suggest a low potential for harmful effects, testing regimens are based on the premise that long-term exposure to large quantities of liquid crystals is not likely. As a result, no chronic animal studies have been conducted that look at cancer and other effects following prolonged exposure to liquid crystals. Data on the potential for liquid crystal release during end-of-life management of LCDs also is absent.
The U.S. Environmental Protection Agency (EPA) has evaluated the potential hazards and risks associated with the release of liquid crystals as part of the Toxic Substances Control Act (TSCA) New Chemicals Program. For several years, companies have been required to submit “premanufacturing notices” to the agency. Based on these reviews, EPA has concluded that there is not an unreasonable risk associated with the manufacture, processing and use of this large class of chemicals. However, this determination is based on theoretical modeling studies, not actual toxicity data. In addition, TSCA doesn't typically require a New Chemical Program review for chemicals that are contained within imported “articles.” Therefore, liquid crystals employed in an imported manufactured item — such as a panel or complete display unit — may not be reviewed by EPA under TSCA. King County's report therefore recommends further evaluation of liquid crystals before a definitive conclusion is drawn regarding potential risks associated with the end-of-life management of liquid crystal compounds.
Researchers also conducted interviews with selected recycling facilities regarding their operating procedures, seeking to gather information on the primary processes currently used to recycle FPD devices. Researchers found many different processing procedures and a wide range of standards for workers' protective gear. The report identifies a need for industry guidance for recycling FPD devices. Researchers found the most probable sources for exposures and releases to the environment were from e-waste dismantling and from activities at recycling facilities such as manual disassembly, shredding, grinding, burning and melting (to reclaim plastics), solder melting and metals processing. More information is needed to develop appropriate risk management guidance.
The report also found that the few state and federal regulations and guidelines addressing end-of-life management of electronic products have limitations or do not address the recycling of specific components.
Where Do We Go from Here?
King County sees this report as an opportunity to further the conversation about the proper management and recycling of devices that contain flat panel displays. This report is a starting place for building a combined industry effort to learn more about the substances contained in flat panel displays and best practices for managing these materials. Ultimately, proper management approaches should protect workers, surrounding communities and the environment.
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