Flat panel display units: less toxic for the environment?

We are all well aware of the lead, mercury and other heavy metals in cathode ray tube (CRT) monitors and televisions but nothing really has been discussed about the hazards associated with flat panel display units. With flat panel display units starting to make their way into the solid waste stream in increasing quantities, this issue needs some attention.

Being a relatively new technology for the mass market, longevity of this equipment is an unknown. U.S. Environmental Protection Agency (EPA) estimates the life of a computer and associated equipment to be less than three years. That does not mean that the computer no longer functions, it simply means the user decides that it is time to trade in or trade up at that point.

Replacement many times means disposal when dealing with this waste stream. The true useful lifespan of such equipment is really six to seven years, one year less for laptop computers. The disconnect is that the equipment does have useful life left but it does not get into the hands of the secondary user market (charities, nonprofits and underprivileged) and is simply disposed of.

We digressed for a moment. This is about the potential environmental concerns of flat panel displays (FPD). While the EPA does require a report for these matters to be filed with them before material or products can be imported into the United States, there are limitations on this data. The limitations are that the data is based on established use and exposure scenarios for the material using a given set of assumptions. These may or may not match real world usage scenarios. Limited toxicity leach testing has been conducted but there are limits to the use of the data associated with the parts of a liquid crystal display (LCD) that would actually be disposed of and what would be recycled.

To begin to answer some of these questions, the Solid Waste Division of the Department of Natural Resources and Parks in King County, Washington (Seattle area) has conducted the first known literature review to: determine the potential chemicals of concern used in FPDs, assess the environmental and worker exposure hazards of the chemicals, and look at work practices and hazards associated with recycling FPDs.

On the environmental side, the King County report identified several areas of concern for FPDs. The first being heavy metals. Those include lead, mercury, antimony, beryllium, cadmium and chromium VI. Remember these concerns are not based on the result of actual testing of a FPD, but based on literature review to identify potential chemicals of concern. Additional chemicals mentioned include brominated flame retardants. Specifically, DecaDBE is identified as being present in large quantities. The toxicity of this chemical is not well known but several countries in the European Union and some states are limiting its use or phasing out the use of DecaDBE.

Something new that really has not been well assessed is the toxicity of liquid (not really a liquid per se) in the liquid crystal displays. While manufacturers of the liquid crystals have run toxicity tests on the material, keep in mind that there are up to 300 different liquid crystal compounds available for use in LCDs. Each LCD can contain a combination of up to 25 of these compounds. Toxicity testing is a challenge 'when considering all the combinations of materials that are potentially available.

A literature review of these compounds and data from Toxic Substances Control Act (TSCA) reports suggests an assumed limited toxicity for the LCDs, but as mentioned, it is based on toxicity modeling associated with use and manufacturing methods and not actual analytical tests run on a discarded LCD destined for a landfill or incinerator.

While this data is based on potential exposure scenarios associated with remanufacturing or recycling of the FPDs, the King County report recommends further investigation. The materials that go into a FPD are known and the environmental issues associated with those materials are also known but the details of the quantities of the chemicals in each piece of equipment and the chemical interactions are unknowns. More importantly, the toxicity of many of the chemicals involved needs further investigation.

On a positive note, from an energy consumption standpoint, FPDs are a more green technology. Let's reserve judgment from an ecological standpoint until the ,data on FPDs is in. The King County report can be read online, on your desktop FPD, by going to the Metro Kinq County website.