When mercury is spilled or leaks from a broken mercury switch, it can be very difficult to properly clean up. If you are conducting a "switch the switch" program or facilitating the removal of mercury switches from automobiles prior to recycling, it is important to be prepared to properly handle a potential mercury spill. Prior to beginning any work on mercury switches, you should secure a plastic tarp or other material under the work space so that any mercury that spills will not spill onto the ground.

The general rule-of-thumb is that if the spill is less than one pound (approximately 2 tablespoons), reasonably contained and on a non-porous surface, then a person may be able to follow mercury spill clean up instructions and do it themselves. If a spill is greater than 2 tablespoons, not on a porous surface or if the mercury droplets are widely dispersed in a room, it would be wise to call for professional assistance.

This general rule-of-thumb is based on the 1 pound (approximately 2 tablespoons) reportable quantity for a release under the federal Comprehensive Emergency Response, Compensation and Liability Act (CERCLA). In facilities that are subject to federal reporting requirements, if mercury in excess of one pound is released to the environment, it constitutes a "reportable quantity" incident and must be reported. State reporting requirements differ; some states require reporting of all mercury spills, no matter the quantity, by individuals while others require reports only of the spills that are greater than 1 pound and only by manufacturing, service and educational facilities, not spills in private homes. Contact your local spill control center or fire department, or state environmental agency for further information on reporting requirements.