CdTe solar panels can be hazardous due to cadmium. Gallium arsenide (GaAs) panels can be hazardous due to arsenic. Some older silicon solar panels may be hazardous waste for hexavalent chrome coatings. Solar panels often contain lead, cadmium, and other toxic chemicals that cannot be removed without breaking the entire panel.
Common problematic impurities in glass include plastics, lead, cadmium, and antimony. According to cancer biologist David H. Nguyen, PhD, toxic chemicals in solar panels include cadmium telluride, copper and indium selenide, cadmium gallium (di), cadmium selenide (di), selenide, selenide, hexafluoroethane, lead, and polyvinyl fluoride. Silicon tetrachloride, a by-product of crystalline silicon production, is also highly toxic.
Studies have shown that heavy metals from solar panels, namely lead and cadmium, can seep out of cells and enter groundwater, in addition to affecting plants. None of this will be achieved quickly or easily, and some solar industry executives will resist internalizing the cost of safely storing or recycling solar panel waste, perhaps for understandable reasons. In addition to developing better recycling methods, the solar industry should think about how to reuse panels whenever possible, since used solar panels are likely to cost more than the metals and minerals they contain (and since their reuse generally requires less energy than recycling). Wise leaders in the solar industry can learn from the past and be proactive in seeking stricter regulation, in line with growing scientific evidence that solar panels pose a risk of toxic chemical contamination.
Unlike other forms of imported e-waste, used solar panels can legally enter countries before reaching e-waste streams. This dilemma is especially vicious in California, Oregon and Washington, as those states began to adopt solar energy from an early age, suggesting that ecological virtue may not necessarily be its own reward. However, both he and Tao are concerned that several U.S. recyclers will sell second-hand solar panels with low quality control overseas to developing countries.
To date, Washington is the only state that requires manufacturers to dispose of panels at a specialized facility. The DTSC described creating a database in which solar panels and their toxicity could be tracked using their model numbers, but it is not clear that the DTSC will do so. Because solar panels are deposited in landfills, the toxic metals they contain can leach into the environment and possibly pose a public health hazard if they reach the groundwater supply. Because the process is expensive and time consuming, it's more convenient for solar energy companies to dump dead panels in landfills or export them to third world countries.
However, about 70 percent of the modules were actually sent for recycling, and recycled metals are found in new panels today. And when Hurricane Maria hit Puerto Rico last September, the country's second-largest solar farm, responsible for 40 percent of the island's solar energy, lost most of its panels. And since solar panels contain toxic materials, such as lead, that can leach as they decay, landfills also create new environmental hazards. The first step is to pay a fee for the purchase of solar panels to ensure that the cost of safely removing, recycling or storing solar panel waste is included in the price of solar panels and is not externalized to future taxpayers.
Most solar recycling plants simply remove valuable silver and copper from cells and then recycle contaminated glass and plastic enclosures by burning them in cement kilns. .