A state administrative agency has rejected a bid by the California Department of Toxic Substances Control (DTSC) to exempt discarded solar cells from some hazardous waste regulations.
Earlier this month, the state's Office of Administrative Law (OAL), which oversees administrative rulemaking, said that it could not approve DTSC's proposal to treat used solar panels as so-called "universal wastes," a hazardous waste category that includes a number of common products such as batteries and household pesticides.
The OAL said that DTSC's proposal would conflict with federal and state hazardous waste handling regulations, in part because of the diverse kinds of solar cells the proposed regulation would cover.
Photovoltaic cells differ widely in the toxicity of their components, from essentially non-toxic crystalline silicon (though other substances used in silicon PV cells can be of concern) to thin-film cells that contain elements such as cadmium, lead, or selenium.
The DTSC had hoped to make handling restrictions for discarded solar panels less stringent, so that hazardous waste companies could do things like remove wiring and other electronic components from the panels for recycling or salvage.
Hazardous waste regulation is complex, and venturing into the regulation books can easily make your eyes glaze over. But the root of the OAL's rejection of the DTSC proposal lies in the difference between two main legal classes of hazardous waste under the Federal Resource Conservation and Recovery Act (RCRA) and California law.
RCRA lists a number of specific hazardous materials that must be disposed of according to its regulations. It also describes classes of hazardous materials according to properties such as reactivity (will it create toxic fumes or explode?), corrosivity, flammability, and toxicity.
RCRA's list of regulated substances is extensive, including any substance created in a long list of industrial processes. But some states have more extensive lists. California state law recognizes a whole separate class of toxic substances that aren't covered by RCRA in that they're not corrosive, ignitable, reactive, or toxic by RCRA standards. The state refers to these hazardous wastes as non-RCRA wastes.
Given that some solar panels contain toxic ingredients such as cadmium, copper, selenium, and lead, they become RCRA wastes when it's time to dispose of them. The DTSC's proposed regulation would have reclassified both RCRA and non-RCRA panels into a new solar panel category of universal waste with less stringent regulation.
Problem is, the standards for handling universal waste in California are less stringent than RCRA's standards. California law says handling wastes covered by RCRA must be subject to state regulations that are at least as stringent as RCRA's requirements. This new rule would have regulated RCRA solar panels less stringently, so the OAL said no.
There were other flaws in the proposed regulation. The DTSC's rule didn't require any kind of recycling of solar panel materials. Nor did it address the effects of having millions of aging solar panels potentially leaking heavy metals into the environment, either in urban settings or in wildlife habitat.
The OAL has invited DTSC to rewrite the rule and resubmit it for consideration. In the meantime, the agency's action is a timely reminder that no technology is without its downside. In order for solar power to be truly clean, we need to make sure to handle solar panels safely when they reach the end of their usable lives.