What is Vapor Intrusion and Vapor Encroachment Assessments?

What is Vapor Intrusion and Vapor Encroachment Assessments?

Have you ever heard of vapor intrusion or vapor encroachment assessments? If not, then you likely don’t know the potential risks associated with these environmental phenomena.

Vapor intrusion and vapor encroachment are terms used to describe hazardous gases seeping into buildings and residential areas due to toxins or pollutants. These gases can be found in soil, water, and air near facilities that contaminate land and create a potential danger to anyone in the areas around them.

Therefore, it is important to understand what vapor intrusion and vapor encroachment assessments are so precautions can be taken. In this article we will discuss what causes them, their different assessment methods, as well as their potential consequences for people who live near contaminated sites.

What is Vapor Intrusion?

Vapor Intrusion is a serious environmental concern that can pose a potential health threat to the occupants of a building. It occurs when volatile chemicals migrate from contamination in the soil or groundwater up into the interior space of a building. This contamination can be caused by on-site sources such as dry cleaning solvents, petroleum products, and other hazardous materials, or it can come from off-site sources such as neighboring businesses. The most common type of contamination is perchloroethylene (PCE), which is highly volatile and toxic.

In order to prevent Vapor Intrusion, it is important to identify any potential sources of contamination and take steps to mitigate them. This includes testing for contaminants in the soil and groundwater, monitoring indoor air quality, and taking measures to reduce vapor pressure in buildings. Additionally, it is important to educate occupants about the risks associated with Vapor Intrusion so they can take appropriate precautions if necessary. By taking these steps, we can help protect people from exposure to hazardous chemicals and ensure their safety.

What is Vapor Encroachment?

Vapor Encroachment is a term used to describe the migration of chemical vapors from contaminated soil and/or groundwater onto a property or near a property. This is different from Vapor Intrusion, which only focuses on the potential for vapors to exist inside a building. The ASTM E2600-10 Standard for Vapor Encroachment Screening defines Vapor Encroachment Concern (VEC) as “the presence or likely presence of chemical of concern vapors in the subsurface of the target property caused by the release of vapors from contaminated soil and/or groundwater either on or near the target property.”

The environmental consulting field still uses the term Vapor Intrusion, which was used in an earlier version of the ASTM Standard (ASTM E2600-08). This is because Vapor Intrusion has been studied more extensively than Vapor Encroachment, so there are more resources available to assess it. However, with increasing awareness about vapor encroachment, more resources are becoming available to assess this issue as well.

Vapor Encroachment assessment as Part of the Phase 1 ESA

The vapor encroachment screen is an important part of the Phase 1 Environmental Site Assessment (ESA). It is used to determine the presence or likely presence of chemicals that concern vapors in the subsurface caused by the release of vapors from contaminated soil and/or groundwater. The vapor encroachment screening process identifies releases in the vicinity of the subject property and, based on the contaminant plume, evaluates the likelihood of vapors migrating to the subsurface of the subject property.

The vapor encroachment screen consists of two tiers. Tier 1 uses federal and state databases to identify sites with potential to affect subsurface vapor conditions. This tier employs a 1/3 mile radius for releases of non-petroleum products and a 1/10 mile radius for releases of petroleum products. Tier 2 involves more detailed analysis such as soil gas surveys, indoor air sampling, or other methods depending on site specific conditions. This tier is used to confirm or refute any potential VECs identified in Tier 1. Both tiers are necessary components for assessing vapor encroachment conditions at a given site.

Does the Guidance for Vapor Intrusion Change from One State to the Next?

Vapor intrusion is a phenomenon that occurs when hazardous vapors from contaminated soil or groundwater migrate into buildings and other structures. The guidance for vapor intrusion varies from state to state, as each state has its own set of regulations and standards. If you need professionals to conduct a soil gas investigation in your area, we can put you in touch with the right people.

Although vapor intrusion guidance may differ from state to state, there are some commonalities between them all. For example, most states require an assessment of potential pathways of contamination before any mitigation efforts can be taken. Additionally, many states require periodic monitoring of indoor air quality to ensure that no hazardous vapors have infiltrated the building or structure. By reading up on vapor intrusion guidelines across different states, one can gain a good base understanding of how it works and what steps need to be taken to protect against it.

A More Ambiguous Approach to Regulation: The Case of Vapor Intrusion Regulation in Texas

  • In the context of environmental programs, regulation of vapor intrusion and indoor air has been inconsistent and case-by-case up to this point.
  • The Texas Commission on Environmental Quality does not routinely address this issue in the process of environmental restoration.
  • The United States Environmental Protection Agency has put pressure on the Texas Commission on Environmental Quality to further develop and execute regulations regarding vapor intrusion.

Results of Vapor Encroachment and Future Steps

When it comes to vapor encroachment, there are four possible outcomes of a screening: VEC exists; VEC likely exists; VEC cannot be ruled out, or VEC can be ruled out. Within the framework of a Phase 1 Environmental Site Assessment (ESA), an Environmental Professional (EP) evaluates a particular site to determine whether or not a VEC corresponds to a recognized environmental condition (REC). If you haven’t had a Vapor Encroachment Assessment yet, it’s better to schedule one sooner rather than later. Getting in front of potential issues will help save money in the long run.

RSB Environmental can help with all aspects of the Phase 1 ESA. We have experienced professionals who can effectively assess your facility and make sure it follows all current EPA regulations. Give us a call today to find out more about our services and how we can help you protect your business from costly environmental liabilities.

If you need any assistance with your Vapor Intrusion and Vapor Encroachment Assessments please email info@rsbenv.comWe look forward to hearing from you.