You may not realize it, but your house — and your family — could be exposed to cancer-causing gas that's killing hundreds of New Jerseyans each year.

New Jersey officials are warning people about radon, a naturally occurring, cancer-causing radioactive gas with no color, odor or taste, that is responsible for 566 deaths among New Jersey residents each year. At least 23 Patch communities are considered to have a high risk of exposure to the gas, while another 57 towns have a moderate risk and the remaining 24 have a low risk (see list and map below).

The New Jersey Department of Health is joining with the New Jersey Department of Environmental Protection this month in urging all residents to protect their family's health by testing their homes for radon. Gov. Chris Christie issued a proclamation declaring January as Radon Action Month in New Jersey, noting that radon moves from the soil and into homes through cracks and openings in the foundation.

One in six New Jersey homes has elevated levels of radon, but only 30 percent of households across the state have been tested, state officials say. "Testing your home is the only way to know if your home's radon level is high," Health Commissioner Cathleen Bennett said in a press release. "Radon problems can be fixed by installing a radon mitigation system."

Radon is the second leading cause of lung cancer. It is the leading cause among non-smokers. The Environmental Protection Agency estimates that 86 percent of radon-related lung cancer deaths occur among current or former smokers.

"The risk of developing lung cancer is highest among smokers who are also exposed to radon," Bennett said. "If you smoke and your home has high levels of radon, your risk of getting lung cancer is especially high. In addition to testing their homes, smokers should also take steps to quit smoking."

The state Department of Environmental Protection has a list of certified companies that provide radon testing services, or residents can purchase do-it-yourself test kits from hardware stores, home centers or directly from certified companies through mail order. For more information about the NJDEP radon program, call the NJDEP Radon Program at (800) 648-0394. Here is the list: