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1,4-Dioxane: The Latest Emerging Vapor Intrusion Issue

1,4-Dioxane: The Latest Emerging Vapor Intrusion Issue

Jul 21, 2022
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1,4-Dioxane is an emerging contaminant.  Like “traditional” volatile organic compounds, it has the potential to volatilize and enter indoor air.  This article explores why businesses should consider conducting a VI assessment when evaluating 1,4-Dioxane releases for site investigations or real property due diligence.

For additional background regarding 1,4-Dioxane, please refer to BCLP’s prior Client Alert, which discusses how this chemical has been used in certain products and industries.

I. Why 1,4-Dioxane is a Concern

According to the U.S. Environmental Protection Agency (“EPA”), 1,4-Dioxane moves rapidly from soil to groundwater.  This factor is an important consideration because VI issues arise when contaminants appear beneath a building and vaporize into indoor air within the building.

EPA and many state agencies have determined that 1,4-Dioxane is a health risk to human beings at certain concentrations, although it is not listed as a known human carcinogen at this time.  Studies used by EPA and the National Library of Medicine have determined that 1,4-Dioxane causes cancer in animals.  Below is a summary of current agency conclusions as to human health:

Agency

Conclusion 

EPA

Likely to be carcinogenic to humans

International Agency for Research on Cancer

Possibly carcinogenic to humans

Agency for Toxic Substances and Disease Registry (”ATSDR”)

May cause cancer

Department of Health and Human Services

Reasonably anticipated to be a human carcinogen

 

II. 1,4-Dioxane and VI Issues

A VI issue of concern occurs when contaminated gases in the subsurface intrude into a building’s indoor air at concentrations that approach or exceed health benchmarks.  In 2016, EPA established advisory Vapor Intrusion Screening Levels (“VISL”) for hundreds of chemicals, including 1,4-dioxane.   

1,4-Dioxane is a potential concern at industrial facilities with groundwater contaminated with 1,4-Dioxane.  But VI problems can be particularly acute as a result of the migration of contamination beneath residences, schools, or other sensitive uses.  Risks are heightened if the contaminated plume is shallow or results in standing water in residential basements.  According to a 2022 article addressing this issue: 

Vapor Intrusion (VI) poses significant environmental problems that can degrade indoor air and pose human health risks. … 1,4-Dioxane [is] a widely used volatile organic compound (VOC) that is found in groundwater, however, this compound has not received much attention in indoor air and measurement methods are not well developed.

Importantly, VI issues have caused a number of seemingly finalized sites to be reopened.  Both the ATSDR and  EPA have issued VI guidance, in part to respond to these situations.  This underscores how important VI issues can be in evaluating 1,4-Dioxane releases. 

III. State Regulations

The federal government has not yet issued an enforceable standard for 1,4-Dioxane in drinking water, much less for VI. 

As conveyed in the chart below, some States have established 1,4-Dioxane VI regulations or standards even absent federal guidance.  These State initiatives seek to limit indoor air exposure issues based on different residential, industrial, or occupational standards.  

This map and the information below is current as of July 19, 2022.

State

State Agency Action

State Indoor Air Standards
for 1,4-Dioxane

Colorado

Colorado Department of Public Health & Environment uses EPA Regional Screening Levels

Regional Screening Level Ambient Air Standards:

Residential:  0.56 ug/m3

Industrial:   2.5 ug/m3

Hawaii

Environmental Action Levels

See Table C:  Indoor Air and Soil Vapor Environmental Action Levels

Indoor Action Levels:

Residential:  0.56 ug/m3

Commercial:   2.5 ug/m3

Massachusetts

Massachusetts Department of Environmental Protection Vapor Intrusion Guidance

See Tables I-A (Residential) and I-B (Commercial/Industrial)

Indoor Air Threshold Values:

Residential:  0.47 ug/m3

Commercial:  2.3 ug/m3

North Carolina

North Carolina Department of Environmental Quality Residential Vapor Intrusion Screening Levels

Note:  In March 2018, North Carolina Department of the Environment published the Vapor Intrusion Guidance

 

Indoor Air Screening Levels:

Residential:  0.56 ug/m3

Vermont

Investigation and Remediation of Contaminated Properties Rule

See Appendix A:   EPA’s Regional Air Screening Levels

Note:  In March of 2020, the Vermont Department of Environmental Conservation published the Vapor Intrusion Guidance

 

Regional Air Screening Levels: 

Residential:  0.56 ug/m3

Industrial:  2.5 ug/m3

Alaska

Target Levels for Indoor Air

See Appendix D

Note:  This is VI Guidance for Contaminated Sites only

Target Levels for Indoor Air

Residential:  5.6 ug/m3

Commercial:  25 ug/m3

Indiana

2022 Screening Levels

See pg. 6

Vapor Exposure -- Indoor Air:

Residential:  5.6 ug/m3

Commercial/Industrial:  25 ug/m3

Illinois

Administrative Code, Illinois EPA VI Information, and Illinois Pollution Control Board Notice of Amendments

See Table G of the third document:  Soil Gas Remediation Objectives

Note:  The information listed above is for p-Dioxane

Soil Gas Remediation Objectives:

Residential:  16 ug/m3

Industrial/Commercial:  30 ug/m3

Construction Worker:  42 ug/m3

Maine

Remedial Action Guidelines

See pg. 52

Remedial Action Guidelines, Indoor Air:

Residential:  5.6 ug/m3

Commercial:  25 ug/m3

Maryland

Maryland Department of the Environment Technical Guidelines for Vapor Intrusion

See Table 1:  Residential; and

Table 2:  Commercial 

Indoor Air Levels:

Residential:  4.9 ug/m3

Commercial:  25 ug/m3

Michigan

Guidance Document for the Vapor Intrusion Pathway

See Appendix D-3:  Indoor Air Interim Action Screening Levels

Soil Vapor Screening Levels: 

Residential:  170 ug/m3

Nonresidential:  400 ug/m3

Nebraska

Nebraska Department of Environment and Energy Voluntary Cleanup Program Remedial Goal

See Table A-2:  Soil Gas Vapor Intrusion Remediation Goals

Note:  This is VI Guidance for the Voluntary Remediation Program only

Soil Gas Vapor Intrusion Remediation Goals:

Residential:  19 ug/m3

Industrial:  820 ug/m3

New Jersey

N.J.A.C. 7:26D Remediation Standards

See Tables 7 (Residential) and 8 (Nonresidential):  Indoor Air Remediation Standards for the Vapor Intrusion Exposure Pathway 

Note:  In May 2021, New Jersey Department of Environmental Protection published the Vapor Intrusion Technical Guidance

Indoor Air Remediation Standards: 

Residential:  0.72 ug/m3

Nonresidential:  2.5 ug/m3

New Mexico

Vapor Intrusion Screening Levels

See Table A-4:  Vapor Intrusion Screening Levels (June 2022, Volume I, pg. A-28)

Vapor Intrusion Screening Levels (Cancer):

Residential:  5.62 ug/m3

Industrial:  27.5 ug/m3

Oregon

Risk-Based Concentrations for Individual Chemicals

See page 3

Soil Gas Vapor Intrusion into Buildings:

Residential:  110 ug/m3

Urban Residential:  270 ug/m3

Occupational:  2,500 ug/m3

Pennsylvania

Land Recycling Program Technical Guidance Manual for Vapor Intrusion into Buildings from Groundwater and Soil

See Table 5:  Indoor Air Statewide Health Standard Screening Values

Indoor Air Health Screening Values:

Residential:  3.2 ug/m3

Nonresidential:  16 ug/m3

 

 

 

States with No Specific 1,4-Dioxane VI Regulations (as of the date of publication): 

Alabama, Arizona, Arkansas, California, Connecticut, Delaware, Florida, Georgia, Idaho, Iowa, Kansas, Kentucky, Louisiana, Minnesota, Mississippi, Missouri, Montana, Nevada, New Hampshire, New York, North Dakota, Ohio, Oklahoma, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, Wisconsin, and Wyoming.

IV. Conclusion

As an emerging contaminant, 1,4-Dioxane is gaining the attention of regulators. Increased regulator attention will drive private party focus in the course of real estate acquisitions and leases, environmental remediation projects, and third-party neighbor concerns.  Your business can take the following actions:

  • Consider 1,4-Dioxane (and VI risks in particular) within environmental due diligence in connection with any real estate acquisitions or leases;
  • Evaluate any applicable 1,4-Dioxane VI standards for States in which you own or operate real estate; and
  • The latest ATSM Standard (E1527-21) used by parties in many real estate transactions encourages, but does require, testing for VI issues in certain circumstances.  The ATSM Standard also acknowledges that emerging contaminants, such as 1,4-Dioxane, may be evaluated if regulated by state law.  

If you have any questions regarding 1,4-Dioxane, please contact Phil Karmel (212-541-2311), John Kindschuh (314-259-2313), or Erin Brooks (314-259-2393).   

Related Practice Areas

  • Environment

This material is not comprehensive, is for informational purposes only, and is not legal advice. Your use or receipt of this material does not create an attorney-client relationship between us. If you require legal advice, you should consult an attorney regarding your particular circumstances. The choice of a lawyer is an important decision and should not be based solely upon advertisements. This material may be “Attorney Advertising” under the ethics and professional rules of certain jurisdictions. For advertising purposes, St. Louis, Missouri, is designated BCLP’s principal office and Kathrine Dixon (kathrine.dixon@bclplaw.com) as the responsible attorney.