Vapor Intrusion Regulation in Texas

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This presentation describes the current status of vapor intrusion regulation in Texas under existng rules and guidance documents, and points out the ambiguity and case-by-case nature of vapor intrustion regualtion in the State at this time.

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Vapor Intrusion Regulation in Texas

  1. 1. Vapor Intrusion RegulationVapor Intrusion Regulation in Texasin Texas Scott D. Deatherage Dallas, Texas scottddeatherage@gmail.com 214-356-0979
  2. 2. California Regulation of Vapor Intrusion asCalifornia Regulation of Vapor Intrusion as Example of More Defined ApproachExample of More Defined Approach  In 2007, AB 422 amended the California Health and Safety Code to require that risk assessments performed under the jurisdiction of the DTSC include the development of reasonable maximum estimates of exposure to volatile organic compounds (VOCs) that may enter the indoor air of current or future structures on the site. It also adds a section to the California Water Code that gives the Water Board the authority to require a risk assessment for a brownfield site, which must also address the potential for vapor intrusion.  Risk assessments performed under the jurisdiction of either the DTSC or the Water Board must be conservatively conducted to:  address chronic, low level exposures and the cumulative impact of all volatile chemicals;  address the risks to sensitive identifiable population subgroups, such as infants, children and pregnant women; and  require that all maximum exposure scenarios include not only the current use of the property, but also the reasonably foreseeable future use of the prop erty (e.g., current commercial or industrial use, but foreseeable residential use in the future). If a property owner does not want to cleanup the site to allow for future residential use, then the agency may require a deed restriction prohibiting future residential use without further assessment or cleanup.
  3. 3. California Guidance DocumentCalifornia Guidance Document  Department of Toxic Substances Control, California Environmental Protection Agency, Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air (Vapor Intrusion Guidance) (Oct. 2011)  Provides a stepwise and sometimes iterative process for the investigation of vapor intrusion and describes procedures for screening and site-specific evaluation of potential risks associated with this exposure pathway.  Indoor air concentrations estimated from soil gas or groundwater concentrations by fate and transport models for vapor intrusion and/or measured indoor air concentrations are used in the assessment.  Models for estimating indoor air concentrations include default attenuation factors for vapor migration from soil gas or groundwater to indoor air, and default and site-specific inputs to the U.S. EPA version of the Johnson and Ettinger vapor intrusion model.
  4. 4. California Guidance DocumentCalifornia Guidance Document  Eleven Step Process  Step 1, Identifying Spills and Releases  Step 2, Site Characterization  Step 3, Evaluate Whether the Exposure Pathway is Complete  Step 4, Evaluation of Acute Hazard in Existing Building  Step 5, If no acute hazards exist, then the evaluating party should proceed to a Preliminary Screening Evaluation  Step 6, If Step 5 reveals a potentially significant human health risk, the evaluating party should perform an Additional Site Characterization
  5. 5. California Guidance DocumentCalifornia Guidance Document  Step 7, This step is closely related to Step 6 and simply describes the manner in which the data collected in Step 6 should be analyzed.  Step 8, Building Survey and Work Plan Development  Step 9, Indoor Air Sampling  Step 10, Evaluation of Indoor Air Sampling Results and Response Actions  Step 11, Mitigate Indoor Air Exposure, Monitoring, and Implementation of Engineering Controls
  6. 6. EPA Region 9 Approach for TCE  Region 9 has adopted a short-term exposure guideline for TCE that assumes there is a teratogenic impact from TCE.  The EPA Memo sets short-term exposure levels based on a Hazard Quotient, or HQ, calculated from toxicological conclusions developed from the 2011 IRIS Review, including an additional margin of safety.  The short term exposure guidelines require “prompt” (i.e., within weeks) responses to concentrations as low as 2 µg/m3 of TCE in residences and 7 µg/m3 of TCE in commercial buildings for a 10- hour shift.  The short-term exposure guidelines require “urgent” responses, including the possibility of evacuation, to concentrations as low 6 µg/m 3 in residences and 21 µg/m3 in commercial buildings for a ten hour shift.
  7. 7. Texas Regulation of Vapor Intrusion as anTexas Regulation of Vapor Intrusion as an Example of More Ambiguous Approach toExample of More Ambiguous Approach to RegulationRegulation  Regulation of vapor intrusion and indoor air under environmental programs has been ambiguous and case-by-case.  Not addressed regularly in environmental remediation by the Texas Commission on Environmental Quality.  The US Environmental Protection Agency has put pressure on the TCEQ to further develop and implement vapor intrusion regulations.
  8. 8. To WhatTo What ExtentExtent Does the TCEQ RegulateDoes the TCEQ Regulate Indoor Air Emissions?Indoor Air Emissions?  Various statements by the TCEQ and the lack of an actual specific policy and guidance documents to direct parties to address vapor intrusion have left a level of uncertainty with the regulated community as to  the extent to which the TCEQ expects vapor intrusion to be investigated and addressed, or  whether a typical site investigation would need to consider vapor intrusion at all
  9. 9. To What Extent Does the TCEQ RegulateTo What Extent Does the TCEQ Regulate Indoor Air Emissions?Indoor Air Emissions?  The TCEQ does not typically evaluate indoor air, and the TRRP rule is not written to specifically address this exposure scenario; however, since Weston collected indoor air data, the TS elected to evaluate it. Detected constituents in indoor air were evaluated by comparing results to TRRP risk based exposure levels (RBELs) for residential inhalation (AirRBELInh). The inhalation RBELs are conservative health-based values which are protective of long-term or chronic inhalation over 30 years of exposure for 350 days per year, based on adult and child exposure scenarios. RBELs are not available for every chemical detected, so the TRRP guidance was followed to calculate RBELs for those chemicals where information was readily available to do so.
  10. 10. To What Extent Does the TCEQ RegulateTo What Extent Does the TCEQ Regulate Indoor Air Emissions?Indoor Air Emissions?  As another example, if the undeveloped affected property contains COCs that are a common concern for potential indoor vapor intrusion, then indoor vapor intrusion could become a complete exposure pathway at the affected property if building development occurs in the future.  If the indoor vapor intrusion exposure pathway is a reasonably anticipated to be completed exposure pathway, then unless the affected property is determined to be in compliance with indoor vapor intrusion soil and groundwater PCLs, an IC [institutional control] is required. For a deed notice indicate that either future building development should be designed to preclude indoor vapor intrusion from the underlying soil or groundwater, or provide notice that the affected property should be re-evaluated for potential indoor vapor intrusion before developing buildings. For a restrictive covenant, prohibit future building development unless buildings are designed to preclude indoor vapor intrusion from the underlying soil or groundwater, or prohibit building development until a demonstration is approved by the TCEQ that the affected property is protective against indoor vapor intrusion.
  11. 11. To What Extent Does the TCEQ RegulateTo What Extent Does the TCEQ Regulate Indoor Air Emissions?Indoor Air Emissions?  EPA Region 6 historically pressured the TCEQ to develop a more robust vapor intrusion program through more definitive rules and guidance as to how to identify, regulate, and remedy vapor intrusion.  Region 6 has even reviewed TCEQ files for closed sites, particularly those where a Municipal Setting Designation Certificate has been issued.  The TCEQ has indicated at times that only outdoor air (rather than indoor air) is typically addressed under the Texas Risk Reduction Rules (TRRP).  Much of the regulated community has this perception as well.
  12. 12. What Regulations Apply in Texas to VaporWhat Regulations Apply in Texas to Vapor Intrusion?Intrusion?  The Texas Risk Reduction Rules (TRRP) apply in the case of evaluating remediation levels or soil and groundwater in Texas, other than releases of constituents from petroleum storage tanks.  We will focus on non-Petroleum Storage Tank (PST) rules initially, and then discuss the PST regulations.
  13. 13. What Regulations Apply in Texas to VaporWhat Regulations Apply in Texas to Vapor Intrusion?Intrusion?  Certain parties commenting on the proposed TRRP Rule asked that the agency clarify that indoor air is not regulated under TRRP.  The Agency stated that it reserved the ability to regulate indoor air COCs migrating from other media such as soil and groundwater.  The TRRP Rules state that the Agency may require testing of indoor and outdoor air.
  14. 14. Do the Notification Requirements for HumanDo the Notification Requirements for Human Exposure Include Indoor Air Exposure?Exposure Include Indoor Air Exposure?  TRRP Rule requires notice to parties exposed to chemicals of concern  A TCEQ guidance document states that notice is required where the following occurs:  Exposure to vapors in excess of the Tier 1 human health PCL in the basement of a building overlying shallow groundwater containing a COC.
  15. 15. Would the PCL for Indoor Air Be the Risk BasedWould the PCL for Indoor Air Be the Risk Based Exposure Level or an Occupational Level?Exposure Level or an Occupational Level?  The Protective Concentration Limit (PCL) for Air could would be based on an environmental agency calculation or a worker protection calculation, either  the Risk Based Exposure Level (RBEL), or  for occupational exposures, the Occupational Safety and Health Administration (OSHA) or American Conference of Governmental Industrial Hygienists (ACGIH) levels, whichever is lower  The TRRP Rules allow concentrations for worker exposure to be substituted for the RBEL.
  16. 16. Does the RBEL or Worker Exposure LevelDoes the RBEL or Worker Exposure Level Apply to the Notice RequirementsApply to the Notice Requirements??  The notification guidance document and applicable regulation state that the PCLs that would require notice include those for inhalation.  The TRRP requires notice when Tier 1 PCLs are exceeded.  Tier 1 PCLs are the most conservative, and are often used as a screening level for delineation of COCs in environmental media.  The Tier 2 and Tier 3 PCLs are determined using more site-specific data.  For Air, the Tier 1 PCL equals the risk based exposure level for the relevant COC
  17. 17. Does the RBEL or Worker ExposureDoes the RBEL or Worker Exposure Level Apply to the Notice Requirements?Level Apply to the Notice Requirements?  The TCEQ does provide in the TRRP Rule that the applicable Tier 2 or Tier 3 PCL as appropriately derived for the property or site, may be stated in the notice to show the relevant standard, such as the occupational standard, is not being exceeded.
  18. 18. Vapor Intrusion and PST ProgramVapor Intrusion and PST Program  RG-36, Risk-Based Corrective Action for Leaking Petroleum Storage Tank Sites (PDF), is being updated and is currently unavailable. Once the updates are complete, the document will be made available for download.  Clarifications and Amendments for Implementation of RG-36, Risk-Based Corrective Action for Leaking Storage Tank Sites  Customized Texas RBCA software contains a model for the evaluation of volatile emissions from groundwater to indoor air.  “the default building parameter assumptions are likely over conservative for many buildings.”  “the target groundwater concentrations derived to be protective of this pathway may in many instances be the driver for the site unnecessarily.”  “When qualitatively this is a pathway of concern and the target concentrations for this pathway are exceeded, field verification of vapor concentrations may be the logical next step.”  “This pathway may be more appropriate for evaluation when there is a history of reported vapors, or when high concentrations are in close proximity to building foundations and there is reason to be believe that the foundation is sufficiently impermeable to prevent permeation of vapors through the foundation.”
  19. 19. Vapor Intrusion and PST ProgramVapor Intrusion and PST Program  Point of Exposure Evaluation for Indoor Air Risk  Footprint of the building in question must be evaluated.  1994 RG-36 Guidance stated  For occupational exposure, OSHA PELs as targets  For residential levels, all federal and state regulations apply, and the project manager should consult with Texas Department of Health (now the Texas Department of State Health Services)
  20. 20. Vapor Intrusion and PST ProgramVapor Intrusion and PST Program  1994 RG-36 Guidance stated  Target air concentrations only reviewed when  concern of a potential vapor hazard, or  known or suspected indoor air exposure to contaminants  RG-36 under review and it is not clear how vapor intrusion or indoor air issues will be addressed differently, if at all
  21. 21. Recent Positions Taken by the TCEQ Regarding Vapor Intrusion  Reviewing Vapor Intrusion Risk in Most Remediation Sites  Voluntary Cleanup Program Reviewing Vapor Intrusion  Approach to Chlorinated Solvents, Largely Trichloroethylene (TCE)  Greater review if groundwater concentrations are high
  22. 22. Case Study: Existing Building with Acceptable Subslab Vapors  Testing had been conducted below the slab, but not in the building itself  The TCEQ sought deed restriction that would require approval of any changes to the heating and air conditioning (HVAC) of building
  23. 23. Case Study: Existing Building with Acceptable Subslab Vapors  Questioned EPA’s ability and expertise in reviewing HVAC systems  Refused approach as property could not be sold with a requirement to seek TCEQ approval to work on HVAC
  24. 24. Case Study: Site to Be Redeveloped  Property under contract  High TCE concentrations in soil and groundwater  Building to be demolished  TCEQ stated that an engineering control would be required for new construction  Vapor barrier was suggested as a requirement in a deed restriction
  25. 25. Case Study: Site to Be Redeveloped  We asked for a general statement that a vapor barrier be required in a deed restriction  TCEQ stated that it would have to approve any deed restriction and any vapor barrier  To avoid concerns of buyer, we argued that the restriction state a vapor barrier meeting industry standards be required without further TCEQ approval  Agency insisted on approval, but admitted it did not have expertise in vapor barriers
  26. 26. Case Study: Vapors in Building— Worker Exposure Levels Allowed  Existing Office Building  Historic TCE in groundwater at high concentrations around and under building  Tight limestone, little diffusion  Client decided to test for indoor vapors  Detected, but only in winter  Tried to reduce by sealing floors, carbon filtering of air, more outdoor air
  27. 27. Case Study: Vapors in Building— Worker Exposure Levels Allowed  Despite all actions, still vapors in building  However, below AGCIH levels  Client followed rules to provide notice under Tier 1 PCL  Obtained approval from TCEQ for Tier 2 PCL for TCE
  28. 28. Case Study: Vapors in Building— Worker Exposure Levels Allowed  Obtained approval for ACGIH levels  Prepared health and safety plan  Because of worker expressed concern, and other concerns, company decided to move workers to another building until vapor issue resolved
  29. 29. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  Existing Manufacturing Building  Historic TCE in groundwater at high concentrations around and under building  Tight limestone, little diffusion  Client decided to test for indoor vapors  Detected, but only in winter  Tried to reduce by sealing floors, carbon filtering of air, more outdoor air
  30. 30. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  TCEQ sent letter requesting indoor air testing  Despite all actions, still vapors in building  However, below AGCIH levels  Client followed rules to provide notice under Tier 1 PCL  Obtained approval from TCEQ for Tier 2 PCL for TCE 
  31. 31. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  Obtained approval for ACGIH levels  Prepared health and safety plan  However, the TCEQ sent a letter that greatly surprised us, and called into question the TCEQ’s approach to vapor intrusion generally and TCE specifically
  32. 32. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  TCEQ letter stated that company was in compliance with applicable regulations  Met notification requirements for Tier 1 PCL for TCE  Health and Safety Plan was submitted  ACGIH level would be the exposure level for commercial/industrial workers  This would be the Tier 2/Tier 3 PCLs
  33. 33. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  The letter, however, raised issues beyond the applicable regulations  The TCEQ decided to “recommend” other actions beyond the regulations  Recommended that actions be taken to address “short-term” exposure to TCE  Recommended that “precautionary” notification be given to workers  “Pregnant women (and those who may become pregnant) are the main concern
  34. 34. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  The letter, however, raised issues beyond the applicable regulations  The first eight weeks of pregnancy are of primary concern  “It is important for workers t be made aware of this potential risk as well as suggesting ways for pregnant women (and those who may become pregnant) to immediately mitigate potential exposure, such as limiting time the the affected areas.”
  35. 35. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  The letter, however, raised issues beyond the applicable regulations  Recommended that the Health and Safety Plan be revised to reflect actions to address short-term exposure, and to revise sampling methodology and frequency of sampling to address this concern
  36. 36. Case Study: Vapors in Building—Worker Exposure Levels Allowed, or Not?  The TCEQ approach is similar to EPA Region 9 approach  Similar to approach taken by California  Apparently, EPA is encouraging states to take this approach  But it is beyond regulatory requiremnts, but puts company that might not follow it in a difficult position  “Damned if you do, damned if you don’t” situation
  37. 37. Practical Questions for Parties DealingPractical Questions for Parties Dealing with a Potential Vapor Issuewith a Potential Vapor Issue  Should the switch to an occupational level be pursued?  If the TCEQ does not require soil vapor or indoor air sampling, should it be tested?  Should employees be left in area exceeding a RBEL?  How should the vapor issues be discussed with employees?  How do you address off-site issues? Commercial/Industrial? Residential?
  38. 38. Transactional Concerns  Will OSHA/ACGIH levels be acceptable to a buyer?  Lender?  With Municipal Setting Designations being available in certain Texas cities, will vapor issues become more of an issue?  What will be the future outcome of TCEQ and EPA discussions and TCEQ development of vapor intrusion guidance?
  39. 39. Transactional Examples  Shopping Center with PCE contamination  Seller only willing to agree to address to worker exposure levels  Query whether that would be acceptable to buyer or lender base on current TCEQ position  Building next door to gas stations  Buyer wanted to delay sale until potential vapor from gasoline resolved  Would not accept testing and passing benzene PCLs for air in building or subslab
  40. 40. Conclusions  TCEQ positions in some ways as strict or stricter than other states  Using “recommendations” to attempt to pressure companies to do more than regulations require  TCE science of impact on women based on single rat study; arguably questionable science  EPA approach to get states to follow this approach may not be appropriate

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