Insurers have long wrestled with claims for soil and groundwater pollution under both pre-1986 commercial general liability (CGL) policies and modern environmental impairment liability policies, but recently a new trend in environmental claims has picked up steam — vapor intrusion (VI).

Vapor intrusion is the migration of underground contaminants in soil gas (often volatile organic compounds [VOCs], such as PCE or TCE, or gasoline constituents such as benzene) into a structure above. Contaminated soil vapor enters a building through cracks or other openings in the building's foundation. Even low levels of such contaminants may harm human health and impact property values. Think naturally occurring radon gas seeping into a basement, but from a manmade source.

Regulators now focus on VI and regularly reopen previously remediated sites to investigate VI. The plaintiff's bar is on the scent, and defending VI cases often requires expensive experts and counsel. As VI continues to garner increased attention from scientists, regulators and lawyers, insurers should be aware of the issues associated with VI and employ strategies to help mitigate their VI liabilities.