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Vapor Intrusion is in the Air

Mon, 07/24/2017 - 10:28 -- admin25

by Michael Goldman

Recent advancements in toxicological science have shown that exposure to certain vapors carries much greater health risks than had previously been anticipated. That in turn, is driving down the safe exposure limits set forth by federal and state environmental regulators. For instance, in Minnesota, the new long-term health exposure to fumes from dry-cleaning solvents has dropped ten-fold (20 to now only 2 parts per billion) from what was considered acceptable just a few years ago. The dramatic drop was based largely on a study which indicated that long-term exposure to certain solvents at even low concentrations can cause cancer as well as fetal developmental problems in pregnant women.

The above phenomena—typically referred to as “vapor intrusion”—is becoming an emerging area of interest across the country to regulators, buyers, sellers, lenders, developers, environmentalist as well as homeowners who might be impacted by nearby operations. At least 40 states (excluding Texas) have or are in the process of developing guidance concerning vapor intrusion and many now have “emergency action” levels (e.g., evacuation) at values that were of no concern to regulators less than a decade ago.

According to the EPA, vapor intrusion occurs when there is a migration of volatile organic compounds (VOCs) from any subsurface source such as contaminated soil or groundwater into an overlying building. Vapors move through the soil and seep through cracks in basements, foundations, sewer lines and other openings into buildings and homes. Typical VOCs which cause vapor intrusion include petroleum products like gasoline and diesel fuel, as well as chlorinated solvents like the dry-cleaning chemical tetrachloroethylene, also known as perchloroethylene (PCE) and the degreasing solvent trichloroethylene (TCE).

Usually sites that are the source of vapor intrusion have been known about for years. Some have even been fully remediated to the satisfaction of state and federal regulators. However, in the past the regulators did not view contaminated sites in terms of their ability to contaminate indoor air. Instead, they were primarily concerned about impacts to groundwater and soil. Groundwater ordinarily does not need to be cleaned up unless it is the source of drinking water. In Texas, the Municipal Setting Designation (MSD) has been a successful tool in limiting the need to clean up contaminated groundwater in this regard. In addition, some remedial approaches can allow contaminated soil to stay put if a concrete slab prevents its exposure to others.

However, vapors are different. After all, one might prevent a person from drinking or ingesting contaminated groundwater or soil, but one cannot likewise prevent that same person from breathing air, contaminated or otherwise. Adding to the concern, the vapors are usually odorless, colorless and undetectable without special testing equipment. As a result, the vapors can build up to a point where the health of the residents or workers in those buildings are in jeopardy, like what occurred with radon in the 1980s.

The above has led to a lot of anxiety in several parts of the country. For instance, Michigan estimates there could be as many as 4,000 sites across the state where vapor intrusion might be occurring. Minnesota’s vapor intrusion program regulator has said, “It’s like working on an engine while the car is driving down the road.” And New York and Massachusetts have even re-opened several sites which were previously closed to re-evaluate them for potential vapor intrusion concerns—often at unsuspecting off-site properties whose owners were unaware there was even an issue.

In addition, lawsuits have been filed which stem from vapor intrusion issues. For instance, in 2016 a class action suit was filed on behalf of several residents against Northrop Grumman Corporation in New York claiming its nearby steel operations led to vapor intrusion in their homes. The residents are seeking $500 million in damages. In 2015, a similar class action was filed against General Mills in Indiana claiming its operations led to vapor intrusion into residents’ nearby homes. Several cases have also been filed in Nevada, California and Wisconsin by property owners against dry cleaners and shopping centers claiming exposure to vapors from the dry-cleaning operations.

Lawsuits in Texas have not yet followed suit with the rest of the country. However, due to the number of sites previously closed without consideration of their possible vapor intrusion impacts, it is conceivable that such litigation will soon follow.

Michael Goldman is the founding partner of Goldman Law, PC. He can be reached at

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