Avoid Vapor Intrusion Risks When Acquiring and Developing New Property

Vapor intrusion (VI) is the migration of chemical vapors from the subsurface into buildings and is a frequent problem at contaminated sites. If uncontrolled, chemical vapors can migrate into buildings and pose a risk to human health. Vapor migration in the subsurface, through building foundations, and within buildings is complex and influenced by many natural and human-caused factors. In response it is critical for anyone acquiring or developing new property to avoid vapor intrusion risks in order to protect people from exposures that may lead to adverse health effects. 

The state of California has outlined and described a four-step process for Vapor Intrusion testing to determine whether buildings located near known or suspected subsurface VFC contamination are potentially affected by VI that may pose health risks to occupants. This four-step vapor intrusion guidance process is summarized by these steps:

1. Prioritize buildings that are located near a source of contamination for a VI assessment
2. Collect exterior soil gas samples that will determine if buildings have potential for VI.
3. Collect indoor air, sub slab soil gas, and outdoor air samples in all buildings found to have potential VI risks.
4. Evaluate the need to manage current and future VI risk based on both indoor air concentrations and soil gas concentrations.

There has recently been growing concerns and heightened attention by regulatory agencies and the public around the protection of building occupants from exposure to pollutants from vapor intrusion (VI). As a result anyone acquiring or developing property must perform their environmental due diligence and pursue a thorough assessment of VI risks. Any failure to seriously assess and manage VI risks by new landowners is likely to incur consequences from State and Federal agencies. These consequences could include the potential loss of Superfund liability protections, greater exposure to toxic tort liability, and the potential loss of marketability and usability of the property in question.

The importance of effectively managing VI risks requires that experienced environmental professionals become involved in the testing process. Their professional vapor intrusion guidance will include careful analysis of the property site conditions, site data, and the consideration of the possibility of short-term and long-term obligations for remediation efforts that could be imposed on new property owners in order to mitigate soil vapor intrusion conditions.

Prospective land buyers and developers will typically engage in environmental due diligence well before they purchase any potentially contaminated properties. They do this for many reasons but primarily because they need to conduct an “all appropriate inquiry” (AAI) in order for them to qualify for landowner liability protections according to CERCLA (aka Superfund) regulations. Meeting these federal AAI requirements is a stringent process.  Developers most often hire experienced environmental consultants who will conduct what is known as a Phase I Environmental Site Assessment (Phase I ESA) that complies with all relevant EPA Standards.

In the performance of a Phase I ESA these consultants are required to assess whether there exists potential for releases and/or migration of vapor pollutants. If your chosen consultants are lacking in experience in these Phase I ESAs, they may fail to critically assess all the risks that the intrusion of pollutant vapors could present within structures planned for or already existing on the property.

The State of California’s Department of Toxic Substances Control (DTSC) has written guidance documents that deal with numerous aspects of soil vapor intrusion. These include guidance on the performance of soil gas investigations, the evaluation and mitigation of subsurface VI to indoor air, the remediation of areas that are sources of these vapors and the performance of long-term on site monitoring.

Any evaluation needed for determining the potential for and mitigation of VI conditions on a property for development or purchase will require that a specialized environmental consultant be employed. A sufficiently qualified consultant should meet the following criteria:

• Significant experience in full VI conditions assessment, which includes understanding the potential sources and pathways for VI contamination as well as possible effects from non-VI vapor sources like auto exhaust or other on site sources.
• Experience with conducting all VI investigations, such as soil gas, sub-slab, and indoor air testing.
• Must be knowledgeable of subsurface geological and hydrogeological conditions in the local geography, as well as previous site and requirements and guidance for VI (Phase I and Phase II Assessments, and any applicable State and Federal regulatory standards.
• Experience with the design, installation, operation and maintenance of effective VI mitigation systems.

Employing the services of environmental testing services with the kind of experienced track record outlined in the previous section will serve you well over the long haul. Not only will they help to keep occupants of buildings on your property safe from toxic gases, but you will remain in compliance with all the testing requirements so that you can maintain liability protections.

In addition, an experienced laboratory or testing service is much more likely to discover existing VI mitigation structures in place that need only to be retrofitted to meet the newest standards. Or for developers they could work with you to design and incorporate mitigation structures into the property development plan rather than going back afterwards to retrofit the mitigation structure into place. These scenarios would keep the needed costs for any VI mitigation systems to a minimum while maintaining full compliance with regulations and maintaining the full value of the property and its development.

Torrent Laboratory is the leader in Environmental Site Assessments in California and Hawaii. Our testing capabilities, customer service, chemist qualifications, TATs and testing equipment meet and exceed even the highest standards for quality.  

Soil Vapor Testing

At Torrent, we offer two types of soil vapor intrusion sampling: regular and low-level reporting.

The regular TO-15 test method, which has reporting limits of around 0.5 ppbv, is sufficient for most soil vapor monitoring. For residential or commercial environmental screening levels (ESLs), we offer low-level reporting. We use the TO-15 SIM technique, a sensitive methodology that can report data at the 0.005 ppbv level, ideal for the most precise applications.

Ambient Air Testing

As air analysis has evolved, so have we. In addition to offering ambient air testing, we continually invest in new methods, technologies, and procedures to offer the most advanced testing available. We supply data for a range of air methods, including NIOSH, OSHA, ASTM, and EPA Air Compendium Methods (TO, CO, IO). Our unwavering commitment to quality is inspired by increasing environmental awareness and accountability, our clients’ needs, and our dedication to the continual advancement of testing and analysis.

Ambient Air Monitoring

For the most accurate results and for full remediation we offer ambient air monitoring services to give you full assurance and peace of mind.

Vapor Intrusion Guidance and Mitigation Expertise

Our experience over 25 years has taught us all of the in’s and out’s of the testing and mitigation processes and we will be there to help you find the optimal solution if any problems arise.

Newest Technologies

We are always committed to working with you to provide you with the most innovative testing technologies available to us. In this way we will continually offer the best results for your vapor intrusion assessment project. 

Torrent Laboratory provides the most advanced capabilities in the region. Our full-service lab offers a host of advantages including: 

• Highest certifications 
• Fastest possible TAT in the industry
• Unrivaled technical and customer support
• Unparalleled on-time performance
• Impeccable quality 
• Competitive pricing 
• Convenient geographic location

Trust Torrent as your premier environmental testing laboratory for California and Hawaii.