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New Rules for Contractors Disposing of Mercury Thermostats

SACRAMENTO — Beginning July 1, 2013, new rules take effect in California for both C-20 (Warm-Air Heating, Ventilating and Air Conditioning) and C-21 (Building Moving Demolition) contractors who dispose of out-of-service thermostats containing mercury. The new regulation requires the contractor to put his/her CSLB license number on the thermostat container or provide it at the collection location accepting the device.

The new regulations were adopted in May by the California Department of Toxic Substances Control (DTSC) as the final part of the Mercury Thermostat Collection Act of 2008.

Though no longer sold in California, DTSC estimates up to 10 million mercury thermostats are still in California businesses and homes.

C-20 contractors and C-21 contractors are seen as a critical link in proper disposal of obsolete thermostats that contain the toxin mercury. The new DTSC rules also will help identify contractors not participating.

The nonprofit, industry-funded Thermostat Recycling Corporation operates about 350 collection sites in California that accept and safely recycle old thermostats. Contractors can find the nearest collection site by going to and filling in a ZIP code.

Under the new regulations, collection sites will provide the number of mercury thermostats received and the contractor license numbers to manufacturers, who in turn submit an annual report to DTSC. The regulations require manufacturers to collect and recycle more than 32,500 mercury thermostats in the second half of 2013, or 30 percent of the estimated number of the devices that become waste. Recycling goals will increase for the next five years.

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