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Environmental Due Diligence

PA Act 2 Challenges — Mercury Vapor Intrusion 

PADEP’s New Soil Vapor Screening Values Are Helpful (At Some Sites)

2022 brought a new headache to the Act 2 process in Pennsylvania – the need to evaluate possible Mercury vapor intrusion to buildings.

Mercury sampling

The Problem
One of the requirements of Act 2 has always been that the vapor intrusion pathway to buildings must be evaluated for substances of vapor intrusion concern. But this had previously been reserved for organic compounds in soil or groundwater — not for metals.  In 2022, because of its volatility, Mercury was added to the list of regulated substances needing a vapor intrusion assessment as part of PADEP’s Act 2 approval process.  And mercury is sometimes detected at concentrations exceeding Act 2 Statewide Health Standards in “historic fill” in urban areas.

The Dilemma
Unfortunately, the mercury vapor assessment process proved to be challenging, as the PADEP had not yet published screening values to perform the evaluation.  Also, US EPA Regional Screening Levels are not directly applicable in many instances.  And pursuing the Site Specific Standard for Mercury in soil instead of the Statewide Health Standard can add another big layer of unexpected complexity. 

A Partial Solution
The process gained some clarity in October 2022, when the PADEP issued vapor intrusion screening values for indoor air, sub-slab, and near source soil gas samples that can be applied within the Act 2 program.  These new screening values begin to solve the problem, as they provide a more concrete method for evaluating possible vapor intrusion to onsite and offsite buildings.  But you still need to collect soil gas samples to use those screening levels, as screening values are still not yet available for soil or groundwater.

Options:  
For sites where mercury vapor is identified as a potential concern, and relief of cleanup liability is desired for mercury in soil, two primary options exist: 

  1. Mitigate the vapor intrusion pathway – This option typically involves the use of a vapor barrier and/or sub-slab depressurization system.  If not already included in the cleanup plan for your site, the addition of these systems to a building can prove to be an unnecessary expense for sites where mercury exists at low levels or in a form that does not produce appreciable vapors.
  2. Collect soil gas samples to evaluate the vapor intrusion pathway – This option involves the collection of air samples from the subsurface, beneath a building slab, or inside a building to compare to the newly published mercury vapor intrusion screening values. This may provide options that eliminate the need to install potentially costly vapor mitigation systems. While there may be some additional time and cost for this testing, it may be well worth it if it avoids the time and cost needed for installation of a DEP-approved vapor mitigation system.

Evaluation of the threat of vapor intrusion due to mercury is continuing to evolve. Brickhouse has been working with PADEP on several remediation projects involving the issue and continues to find creative ways to ensure the safety of building occupants, avoid significant unnecessary expenses, and work within the regulatory structure to provide liability protections for property owners and land developers.

For more information, or to discuss various options for your property, please contact us at (610) 692-5770 to talk with Steve Huxta or one of our other vapor intrusion experts.

Act 2 Updates: Does Your Act 2 Site Still Require Post-Remedial Activity and Use Limitations?

The November 20, 2021 changes to Act 2 Statewide Health Standards (SHS) have created some beneficial opportunities for some previously remediated properties that still have post-remedial inspections, reporting, and Activity and Use Limitations (AULs).

For example, in the last 6 months: 

  • We helped one client remove the existing requirement for an asphalt cap, allowing unrestricted non-residential use of the property and a much less costly redevelopment project; and
  • Another client gained approval for unrestricted residential use of their property where groundwater use would have previously been prohibited, significantly improving their property value for re-sale.

Specifically for these properties, the changes in the 1,2,4-Trimethylbenzene standards in groundwater and the benzo(a)pyrene standards in soil allowed us to remove burdensome property use limitations and engineering controls.

Example No. 1

A gas station with petroleum releases to the soil was previously closed out under Act 2 using a Site Specific Standard due to benzo(a)pyrene concentrations above the Statewide Health Standard.

Therefore, the soils required a protective cap and annual inspections and reporting.

However, after the standard was raised from 0.58 to 4.2 mg/kg, the soil no longer exceeded the Statewide Health Standards, so we were able to remove the requirement for a protective cap and related post-remedial care obligations.

The removal of the cap and reporting requirements increased the redevelopment opportunities for the site and also improved the property value.

Example No. 2

A heating oil spill impacted soil and groundwater of a neighboring residential property.  Under a PADEP-approved Cleanup Plan, soils were excavated and replaced, and groundwater monitoring wells were installed.  Five years later, the homeowners still couldn’t sell their property because 1,2,4-Trimethylbenzene concentrations still exceeded residential Statewide Health Standards in the groundwater.  

In November, the Statewide Health Standard increased from 15 parts per billion (ppb) to 130 ppb, thus allowing the cleanup and monitoring to be ceased, and an Act 2 release of cleanup liability was issued by the PADEP, with no restrictions.  The change in standard immediately increased the property’s value and ability to be sold. 

The Bottom Line

In certain situations where sites previously received Act 2 cleanup approvals through the use of engineering controls and/or Activity and Use Limitations on the property, there may now be opportunities to remove these burdensome obligations and ultimately improve the future use and value of the property. 

If your property was previously remediated but still has ongoing maintenance, monitoring and/or reporting obligations, Brickhouse Environmental would be glad to review your reports and advise whether these benefits may be available for your property.

Under the Slab: Vapor Mitigation Strategies for Brownfield Development

Ownership and redevelopment of brownfield properties can provide a business opportunity and greatly benefit a community. While there is significant potential for an all-around positive outcome, the owner or developer takes on the challenge of remediating or managing the contamination through working with environmental professionals and regulators. One of the most common challenges in managing contamination on these properties is dealing with vapor intrusion. 

Vapor intrusion can occur when soil or groundwater underneath or adjacent to a building is impacted by “volatile” contaminants, meaning they readily exist as a vapor (i.e., gas). Think of the vapors that emanate from an open can of gasoline or other household chemicals such as paints and stains. When petroleum products or other volatile chemicals are spilled, they can seep into soil and groundwater and become an ongoing source of potentially harmful vapor. When these vapors move through soil and building foundations it can diminish indoor air quality. This is called vapor intrusion and can result in building occupants being exposed to these contaminants while breathing. 

Vapor intrusion issues can be identified during due diligence, site development, or during characterization and remediation of known petroleum or other chemical spills. The nature and extent of the soil and groundwater contamination, as well as existing building conditions all have a significant impact on the best way to manage and resolve the vapor intrusion issue. It doesn’t matter if the building was constructed 200 years ago, 2 weeks ago or planned for construction in 2 months, there is a cost-effective solution. The solutions differ most significantly when considering mitigation of existing or new construction. Continue reading to learn more or call us at (610) 692-5770. 

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New Phase I ESA Standard Redefines “Recognized Environmental Condition”

Through November of 2021, over 300,000 Phase I Environmental Site Assessment (ESA) Reports have been prepared in the United States in connection with the sale, purchase, financing, and development of commercial real estate.  The primary purpose of conducting a Phase I ESA is to identify whether there are Recognized Environmental Conditions (RECs) in connection with a property being investigated. 

With the release of its updated Standard Practice, ASTM E1527-21, the American Society of Testing and Materials (ASTM) offered several significant changes.  One of the most overlooked yet potentially significant changes involves the definition of a REC.  

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Amendments to PA’s Act 2 Statewide Health Standards – May Have Site-Specific Impacts on Environmental Assessments and Cleanups

On November 22nd, the Pennsylvania Department of Environmental Protection (PADEP) published updates to the Chapter 250 regulations for environmental investigations and remediation under Pennsylvania’s Act 2 voluntary cleanup program. The rulemaking includes changes to many Statewide Health Standards based on new scientific information, and adds groundwater and soil standards for PFOA, PFOS and PFBS – three common PFAS chemicals.

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How Can a Human Health Risk Assessment Benefit You?

The benefits of performing a Human Health Risk Assessment (HHRA) are often underestimated or overlooked entirely when landowners or even potential landowners are making decisions regarding an appropriate path forward for their Site. Whether it’s during a Phase II Environmental Site Investigation (ESA) or through a Pennsylvania Department of Environmental Protection Agency (PADEP) Land Recycling Program (Act 2) Cleanup, HHRA’s can be a time- and cost-effective tool for ensuring that current and/or future receptors are protected from contaminated media.

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