Emergency Response: Identifying and Mitigating Petroleum Vapor Intrusion at an Active Gasoline Station

Nottingham, Maryland

ARM Group managed an investigation at an active gasoline station in Nottingham, Maryland, following the detection of petroleum vapors inside the onsite building. The multi-phase investigation, approved by the Maryland Department of the Environment (MDE), was part of an ongoing effort to ensure regulatory compliance and protect environmental and public health.

The Challenge

In October 2024, ARM was contacted late on a Sunday night by the client regarding employee complaints of odors inside the building. Within 12 hours of ARM collecting a sub-slab vapor sample, laboratory results confirmed the detection of volatile organic compound (VOC) concentrations linked to petroleum products. ARM immediately worked to mitigate vapors and restore safe conditions for the employees while maintaining compliance with MDE regulations.

The Solution

Over the following months, ARM worked closely with the client and MDE to implement remedial measures to prevent continued vapor intrusion.

  • Two ARM Group field technicians examining soil cores on-site during petroleum vapor intrusion investigation.

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    Two ARM Group field technicians examining soil cores on-site during petroleum vapor intrusion investigation.

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  • Prepared soil core samples laid out for review alongside field notebook during environmental site assessment.

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    Prepared soil core samples laid out for review alongside field notebook during environmental site assessment.

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  • Field equipment and safety perimeter set up in gas station parking lot for vapor intrusion mitigation work.

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    Field equipment and safety perimeter set up in gas station parking lot for vapor intrusion mitigation work.

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  • Field crew conducting vapor intrusion investigation and sonic drilling operations at an active fuel station site. Equipment and safety perimeter are in place.

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    Field crew conducting vapor intrusion investigation and sonic drilling operations at an active fuel station site. Equipment and safety perimeter are in place.

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To evaluate subsurface conditions, ARM developed an investigation plan, which included:

  • Installation and sampling of indoor and outdoor vapor monitoring points and sampling of indoor air.
  • Installation and sampling of nine monitoring wells to assess soil and groundwater conditions.
  • Use of sonic drilling technology to minimize surface disruption while improving sampling efficiency.
  • Real-time data analysis to guide remediation strategies.
  • Regulatory coordination with MDE to ensure compliance and site safety.


The subsurface investigation was implemented in March 2025. 

The Outcome

The remediation efforts allowed the gasoline station to resume operations within a timely manner with MDE approval. Following data analysis, ARM will develop a long-term monitoring and corrective action plan based on investigation findings, ensuring continued compliance and environmental safety.

Key Services Provide:

  • Emergency Response & Vapor Intrusion Mitigation
  • Regulatory Compliance & Agency Coordination
  • Subsurface Investigation & Groundwater Assessment
  • Sonic Drilling for Minimal Site Disruption
  • Remediation Planning & Monitoring

ARM Group has a proven track record of emergency response success, delivering Precise. Responsive. Solutions. that help clients maintain operations while addressing environmental challenges.



Click here to learn more about our environmental & emergency response services.