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Prevailing Trends in Vapor Intrusion - Addressing the Trichloroethylene Assessment
Active soil depressurization provides an effective means for addressing vapor intrusion issues caused by tricholorethylene in soil. Tricholoethylene was recently listed as a human carcinogen by the Environmental Protection Agency.
ADDRESSING THE TRICHLOROETHYLENE ASSESSMENT
Subsurface vapor encroachment, commonly referred to as vapor encroachment, is gaining attention at the federal, state, and local levels with final Subsurface Vapor Intrusion Guidance slated to be released by the U.S. Environmental Protection Agency November 30, 2012. The Environmental Protection Agency (EPA) is evaluating changes to the Hazard Ranking System and related policies to specifically address vapor intrusion. In particular, attention was recently drawn to trichloroethylene, with final assessment as a human carcinogen and human noncancer health hazard being announced on September 28, 2011. Policy change and rulemaking will inevitably result in changes to the legal and regulatory environment under which commercial and residential building owners conduct business, including employee or resident conditions, audits and assessments, valuations, sales, and use. Litigation surrounding interior air contamination sourced from plumes of volatile chemicals of concern and petroleum hydrocarbon chemicals migrating through the vadose, or unsaturated, zone of soil, has long been a source of concern for building owners, employers, property managers, and developers. In recent years, attention has been drawn to the relative absence of guidance on subsurface vapor intrusion.
In the December 14, 2009 report from the U.S. Environmental Protection Agency – Officer of the Inspector General entitled Lack of Final Guidance on Vapor Intrusion Impedes Efforts to Address Indoor Air Risks (Report No. 10-P-0042), measures, methods, and standards regarding subsurface vapor intrusion were all called into question. This report acknowledged the following:
1. That “current and former contaminated sites could have extensive vapor intrusion issues and pose a significant risk to the public”.
2. That toxicity values of some chemicals commonly associated with vapor intrusion, particularly trichloroethylene and perchloroethylene (tetracholoethylene)
3. Risks from petroleum hydrocarbon vapors were not adequately addressed.
4. That “interim remedial measures” did not sufficiently provide guidance as to installation, monitoring, operation, and maintenance of vapor intrusion mitigation systems.
5. That updated measures and training are deemed necessary.
These findings raised attention as to the seriousness of subsurface vapor intrusion, and initiated a number of studies and draft papers by the Environmental Protection Agency, including Background Indoor Air Concentrations of Volatile Organic Compounds in North American Residences (1990 – 2005): A Compilation of Statistics for Assessing Vapor Intrusion (June 2011) and a draft paper on petrochemical vapor intrusion issues entitled EPA's Petroleum Vapor Intrusion Guidance (July 2011). With increased awareness and studies will come rulings and legislation which will impact the technical, applied, and legal climate surrounding how we encounter, mitigate, and monitor subsurface vapor intrusion.
In addition to technical papers, the Environmental Protection Agency has started providing the public with information to help them to understand sources of vapor intrusion and methods for mitigating these vapors. In particular, diagrams such as Figure 1 (OSWER – Basic Information)
These systems, called radon mitigation systems, remove soil vapors from below basements or foundations before they enter homes. Vapors are vented outside of the homes where they become dispersed and harmless. These systems use minimal electricity and do not affect heating and cooling efficiency. They also prevent radon from entering homes – an added health benefit especially in radon prone areas.
By extension, the same principles for homes apply to other structures, but on a larger scale, often with additional factors, such as occupational health and safety.
Building owners, commercial realtors, employers, and investors are aware of the fact that increased public awareness of vapor intrusion may increase potential for litigation. The EPA has had vapor intrusion guidelines in place since 2002 under the Resource Conservation and Recovery Act (RCRA), but with focused attention on vapor intrusion as a pathway for chemical exposure, thus a component of the Hazard Ranking System used to place a site on the National Priorities (Superfund) List, the potential for loss of property value, litigation under RCRA, and class action lawsuits under OSHA regulations. As a result, many building owners are opting to take pre-emptive measures for vapor intrusion, and some new construction projects are including vapor intrusion mitigation systems as a component of the physical plant and outlay.
With new regulations on the horizon, successful but cost-effective measures for dealing with vapor encroachment are sought and highly valued. Air Quality Control Agency is a company with over twenty-three years of experience with providing solutions and successfully mitigating subsurface soil vapor and radon. We use the EPA recognized method of sub-slab depressurization to remove soil vapors from beneath structure foundations, and utilize a combination of proprietary technologies and vapor barrier installation to mitigate difficult properties. Our company is uniquely qualified to provide vapor intrusion mitigation, drawing on a pool of over 50,000 installations in both commercial and residential settings, and a knowledgeable staff with a combined experience of over 100 years. Our numerous successes include mitigation at military installations, including Fort Knox, mitigation of a site repurposed from a dry cleaning operation to an office complex, and mitigation of numerous retirement communities and multifamily investment properties.
Air Quality Control Agency – Vapor Intrusion Mitigation Division is prepared to provide guidance and direction your resolution program for vapor encroachment. Our motivation is to improve public health through solving vapor intrusion issues at a reasonable cost. Our size, volume, and longevity enable us to be on site, on budget, and on time with your mitigation solution. And our reputation, warranty program, and vision assure your company that continued technical support, including preventive maintenance, system upgrades, and modifications, will be available to address policy changes and corporate growth.
Air Quality Control Agency and Air Quality Control Vapor Intrusion Division invite you to contact or visit us with your vapor intrusion needs. Our company has technical offices in 23 states, coordinated through our Central Headquarters in Lansing, Michigan. We welcome opportunities for competitive bidding and extraordinary mitigation circumstances.
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Air Quality Control Agency is a company with over twenty-three years of experience
with providing solutions and successfully mitigating subsurface soil vapor and radon. We utilize EPA recognized sub-slab depressurization and proprietary technologies.