New ASTM Guidance for Monitoring of Vapor Intrusion Mitigation Systems Published

Vapor intrusion (VI) is a component of most assessments these days.  A common practice in the industry, especially in new construction, is to step beyond the assessment phase and move directly to a presumptive remedy, such as sub-slab depressurization systems (SSDS), under the assumption that this would end the need to worry about future VI issues.  However, as is common with environmental projects, what was thought to be the end of the road is just the beginning of a long process of mitigation verification and system monitoring.  At Cox-Colvin, we saw the need for guidance in this area and worked with a small group of regulators and practitioners to develop a standard approach for the VI community.

In October 2021, ASTM published the “Standard Guide for Development of Long-Term Monitoring Plans for Vapor Mitigation Systems (D8408/D8408M – 21).  This new standard focuses the types of information that should be included in long-term monitoring plans for a wide variety of VI mitigation approaches and techniques, such as:

  • System overview – identifying the issues that led to the installation of the system,
  • Permits needed,
  • Commissioning date,
  • Descriptions of the key components of the systems,
  • Performance goals and projected decommissioning dates,
  • Inclusion of detailed construction drawings,
  • Location of monitoring points,
  • Alarm systems,
  • Inspection procedures and reporting requirements,
  • Manufacturers recommended repair procedures,
  • Decommissioning goals and triggers, and
  • Organizational charts with points of contact.

Included in the standard is a table of example monitoring programs for a wide variety of active and passive vapor mitigation systems that walk the user through four life-cycle elements, which include:

  • Initial Verification (System Startup),
  • Operational Monitoring,
  • Long-Term Monitoring, and
  • Additional Testing.

We were cognizant of the fact that long-term monitoring programs must be cost-effective and easily implementable.  To meet this goal, we proposed a variety of monitoring techniques which rely on a combination of periodic analytical sampling combined with more frequent monitoring of less expensive system performance indicators such as sub-slab-to-indoor air differential pressure (which can be easily completed through cloud-based data gathering systems).   The new standard is available through ASTM. Cox-Colvin has been providing Vapor Intrusion Assessment and Mitigation services to a wide variety of clients since 2004.  We strongly suggest that the ASTM Standard be consulted as you develop your best practices documents for mitigation.  If you need assistance with vapor intrusion projects, or any of your other environmental needs, please feel free to contact us at any time.

On February 1, 2022, in recognition of his efforts in completing the “Standard Guide for Development of Long-Term Monitoring Plans for Vapor Mitigation Systems (D8408/D8408M – 21), Craig Cox was presented ASTM’s Richard S. Ladd Standards Development Award”.

Published in the Focus on the Environment, February 2022


Craig Cox is a principal and co-founder of Cox-Colvin & Associates, Inc., and holds degrees in geology and mineralogy from the Ohio State University and hydrogeology from the Colorado School of Mines. Mr. Cox has over 30 years of experience managing large environmental project implemented under CERCLA and state voluntary action programs. Mr. Cox is the inventor of the Vapor Pin® and has developed a variety of software products including Data Inspector, an internet-enabled environmental database application. Mr. Cox is a Certified Professional Geologist (CPG) with AIPG and is a Certified Professional (CP) under Ohio EPA’s Voluntary Action Program.