Vapor intrusion (VI), the process by which vapors from contaminated groundwater migrate into and accumulate in indoor air spaces, is increasingly becoming a necessary component of every remediation project, and has become a necessary component of environmental due diligence in real estate transactions. The ASTM International 2005 Standard Practice for Environmental Site Assessments now includes VI migration as a component of the Phase I investigation. Recent regulatory changes highlight the importance of a successful community outreach strategy. In March 2013, the New Jersey Department of Environmental Protection (NJDEP) issued its new Vapor Intrusion Technical Guidance,which establishes a complex framework for assessing VI that includes community outreach as a key component of the VI investigation.
The Mechanics of a VI Investigation
A VI investigation is triggered under several scenarios. Any structure within 100 feet of groundwater contaminated with volatile organic compounds or free product must be evaluated for VI. N.J.A.C. 7:26E-1.15(a). If the groundwater contaminant is a petroleum hydrocarbon, the distance triggering an evaluation is reduced to 30 feet. A VI investigation is also triggered if soil, gas or indoor air contamination is otherwise detected above accepted screening levels, or if other information indicates that human health and safety might be impacted due to VI.
