In the fall of 2018, the United States Environmental Protection Agency (EPA) added two new sites to the National Priorities List (NPL) for a reason that never factored into NPL listing in any time in history.  The sites became Superfund sites based solely on subsurface chemical vapor migration and the potential for vapor intrusion (VI) into buildings.

Superfund Sites Consider Vapor Intrusion

Sites become eligible for the Superfund listing based on the Hazard Ranking System (HRS).  The HRS historically considered four pathways:  (1) groundwater migration, (2) surface water migration, (3) soil exposure, and (4) air migration.  Each of these pathway hazards are given a numeric score from 0 to 100.  Sites with a score of 28.5 are eligible to be listed as a Superfund Site (NPL).

With the addition of VI as a potential pathway, we are likely to see more sites, which are, at a minimum, eligible to be listed by the EPA.

Mention "Superfund," and you might have images such as this one. In reality, it's more typically subsurface issues including vapors, that "drive" Superfund and other site investigations.

Mention “Superfund,” and images such as this one are likely to come to mind. In reality, it’s more typically subsurface issues, including vapors, that “drive” Superfund and other site investigations.

Potential Sources of Vapor Can Impact Business Decisions

Superfund listings aside, vapor intrusion, which only a handful of years ago was relatively benign and only peripherally thought about, is here to stay as an exposure pathway that must be considered.  Whether you are buying or selling commercial property or operating an existing company with on-site or off-site historical issues, you need to pay close attention to VI.  

Unlike the widely-covered per- and polyfluoroalkyl substances (PFAS) where regulators are more narrowly focused (Airports, Department of Defense Sites, Landfills, etc.), the potential sources of VI are varied and “commonplace.”  Potential sources of vapor are in just about every community and commonly include dry cleaners and gasoline stations.

Gasoline Stations and Dry Cleaners

According to at least one estimate, there are 570,000 gasoline underground storage tanks (USTs) in the United States.  Gas stations, which are located along busy intersections where commercial properties are commonly bought and sold, have a typical storage capacity of 30,000 to 40,000 gallons of fuel.

As of 2013, there were an estimated 28,000 dry cleaners in the US that use perchloroethylene, or PERC.

More typically, it is the old gas stations and old dry cleaners that are concerns.  New gas stations with improved tanks and leak detection systems, as well as newer dry cleaning operations, are far less likely to have significant releases than their predecessors.

Other Sources of Vapor

The above numbers don’t include abandoned sites or sites where there are no records of USTs (See Uh Oh, we just found a UST).

Another source of vapor includes old industrial properties.  While current environmental practices are designed to limit human health and environmental exposures, this wasn’t always the case.  Prior to current environmental management practices, it was not unusual for solvents to simply be disposed by dumping them on the ground.

For example, an old Department of Defense Site we are currently working on literally sprayed airplane wings on the tarmac with trichloroethylene (TCE).  The runoff went straight down into the soil and groundwater beneath the airport.  As you can imagine, this is a significant environmental remediation effort.

Businesses Forced to Close Because of Vapor

Just last year, it was reported by the Michigan Department of Environmental Quality that there may be as many as 4,000 sites in Michigan where VI is an environmental concern.

In the past 12-18 months, we saw several companies in Michigan forced to evacuate their buildings due to vapor concerns.  This meant business stopped immediately, and business could not resume until the vapor condition was addressed.

While we suspect there will still be plenty of news coverage on PFAS in 2019, vapor intrusion will still likely drive site assessment, mitigation, and remediation efforts in the foreseeable future.

Do you need help assessing or mitigating a vapor intrusion issue?  We can help.  Feel free to reach out to me with your questions or concerns regarding vapor intrusion.