California, like many states, has a problem with a rapid influx of end-of-life solar panels, despite that a law (SB 489) passed five years ago to help facilitate collection and processing of these materials. The biggest problem, according to Doug Kobold, executive director of the California Product Stewardship Council, is that there is uncertainty as to whether photovoltaic panels (PV) are considered hazardous waste. The Department of Toxic Substances Control (DTSC) is promulgating regulations to get them classified as universal waste, but the agency has been awaiting the U.S. Environmental Protection Agency’s approval of this less onerous classification, and Kobold estimates it could be as late as July before the state gets authorization, if it gets approval at all.
So, for now, PV modules are considered hazardous waste, unless proven otherwise through time- and money-consuming processes. “DTSC requires that each panel be tested to determine if it’s hazardous, and the tests can cost $700 to $1,500. Most landfill operators don’t test them, so many of them are left in limbo. In some cases, they are shipped under a hazardous materials manifest to avoid testing and risk of fines if they are not certain they are hazardous,” says Kobold.
He is happy that California most recently addressed one issue the industry has clamored around. The regulations now explicitly state that integrated devices with built-in solar panels, such as calculators and garden lights, are considered electronics, meaning they don’t have to be managed the same way as large PV panels but rather within existing infrastructure.
Source: Waste360
Finnish site 
Global site