PART 1. TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
CHAPTER 350. TEXAS RISK REDUCTION PROGRAM
SUBCHAPTER D. DEVELOPMENT OF PROTECTIVE CONCENTRATION LEVELS
The Texas Commission on Environmental Quality (TCEQ, agency, or commission) adopts the amendment to §350.76.
Amended §350.76 is adopted without change to the proposed text as published in the August 30, 2024, issue of the Texas Register (49 TexReg 6702) and, therefore, will not be republished.
Background and Summary of the Factual Basis for the Adopted Rules
The purpose of this rulemaking is to amend 30 Texas Administrative Code (TAC) Chapter 350, Texas Risk Reduction Program (TRRP) rule §350.76, pertaining to the chemical-specific approaches used for developing and demonstrating attainment of the critical human health protective concentration levels (PCLs) for dioxins/furans and dioxin-like polychlorinated biphenyls (PCBs).
The TCEQ rulemaking adoption updates the approach for developing soil PCLs for dioxins/furans and dioxin-like PCBs used for residential and commercial/industrial land use under TRRP. The current approach is covered in the TRRP rule in §350.76(d) and §350.76(e), and the current PCLs are specified in the TRRP rule at §350.76(e)(3). The PCLs contained in the existing TRRP rule were based on a then-current 1998 United States Environmental Protection Agency (EPA) policy memo (OSWER Directive 9200.4-26), which described an approach for addressing dioxins in soil. Since that time, the EPA completed a reassessment of this approach and derived an updated reference dose for dioxins. Based on more recent scientific evaluations, the TCEQ can support the use of a reference dose in the range of EPA's updated value, and that value is reflected in the approach provided in this rulemaking adoption. Upon the effective date of the adopted revisions, any activity conducted pursuant to TRRP must comply with the revised approach for developing dioxins/furans and dioxin-like PCBs soil PCLs used for residential and commercial/industrial land use under TRRP.
Additionally, the rulemaking adoption updates the toxicity equivalency factors (TEFs) related to dioxins/furans and dioxin-like PCBs contained in §350.76(d)(2)(B). Dioxins/furans and dioxin-like PCBs are mixtures of chemical compounds (congeners) with different toxicities. TRRP §§350.76(d) and (e) use TEFs to assess the relative toxicity of the individual congeners compared to the toxicity of the most toxic congener, 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD), within a mixture of dioxins/furans and dioxin-like PCBs. The TEFs are applied as a multiplier of the concentration of each measured congener to calculate a 2,3,7,8-TCDD toxicity equivalency quotient (TEQ) concentration. The resulting 2,3,7,8-TCDD TEQ concentrations for each congener are summed to derive a total 2,3,7,8-TCDD TEQ concentration for the entire mixture. The total 2,3,7,8-TCDD TEQ concentration is then compared to a 2,3,7,8-TCDD PCL to determine the nature and extent of contamination and whether a remedy is required. The TRRP rule provides specific TEFs for various dioxins/furans and dioxin-like PCB compounds and directs persons to use these TEF values when demonstrating attainment of the critical PCL.
When the TRRP rule was promulgated in 1999, the most recent TEF values established by the World Health Organization (WHO) in 1998 were listed in the rule. However, based on evolving science and current data, WHO updated the TEF values in 2005 and continues to develop the most current TEF values. EPA and other regulatory agencies have been using the 2005 WHO TEFs. The adopted TRRP §350.76 rule revision will allow cleanups being conducted under TRRP to adopt the 2005 WHO TEFs or more recent TEFs established by a scientifically valid source that have been reviewed and approved by the executive director. Upon the effective date of the adopted revisions, any activity conducted pursuant to TRRP must comply with the 2005 WHO TEFs, or more recent TEFs established by a scientifically valid source that have been reviewed and approved by the executive director, for dioxin-like PCBs and dioxins/furans.
The TRRP chemical-specific PCL approaches for dioxins/furans and dioxin-like PCBs are being revised in this rulemaking adoption to reflect updated information on dioxin toxicity and address appropriate updates to the WHO TEFs for dioxins/furans and dioxin-like PCBs. Adoption of the rule also provides TCEQ with the flexibility needed to evaluate and adopt more recent TEFs that have been derived since the TRRP rule was first adopted in 1999.
Section by Section Discussion
Subchapter D: Development of Protective Concentration Levels
The commission adopts the amendment to §350.76(d)(2)(B) which removes the figure and the directive for persons to use TEFs specified therein when determining a 2,3,7,8-TCDD TEQ for dioxin-like PCBs. The adopted rule will direct persons to apply the 2005 WHO TEFs, or more recent TEFs established by a scientifically valid source that have been reviewed and approved by the executive director, to the measured concentrations for each of the dioxin-like PCBs.
The commission adopts new subsection §350.76(d)(3). This subsection clarifies that a person may be required to evaluate the adequacy of a response action when the executive director determines that a substantial change in the TEFs alters the calculated TEQ in such a way that results in the actual toxicity of the dioxin-like PCB mixture not being protective of human health and the environment. The rule also specifies that it is possible that a person might not be required to conduct a response action in the case where a significant change in the TEFs affects the TEQ in such a way that reveals a response action is no longer warranted to protect human health and the environment. To maintain the numerical order of the rule, previous subsections (d)(3) and (d)(4) are being renumbered to (d)(4) and (d)(5), respectively.
The commission amends §350.76(e)(1) by removing the directive for persons to use TEFs specified in the figure included in subsection (d)(2)(B), when demonstrating attainment of the critical PCL for 2,3,7,8-TCDD. The adopted rule will direct persons to apply the 2005 WHO TEFs, or more recent TEFs established by a scientifically valid source that have been reviewed and approved by the executive director, to demonstrate attainment of the critical PCL for 2,3,7,8-TCDD.
The commission's rulemaking adoption amends §350.76(e)(1)(B) to clarify that, when homologue-specific analytical data are available, persons shall apply the 2005 WHO TEFs or more recent TEFs established by a scientifically valid source that have been reviewed and approved by the executive director. Additionally, this subsection clarifies that if a homologue class has more than one TEF for different congeners, persons shall use the highest of the latest TEFs that have been reviewed and approved by the executive director for that congener class. Additionally, the rulemaking adoption removes the language specifying that a TEF value of 0.5 be used for the pentachlorodibenzofuran homologue class.
The commission adopts the amendment for §350.76(e)(1)(C) to clarify that, when congener-specific analytical data are available, persons shall apply the 2005 WHO TEFs or more recent TEFs established by a scientifically valid source that have been reviewed and approved by the executive director.
The commission adopts a new subsection §350.76(e)(1)(D). This subsection clarifies that a person may be required to evaluate the adequacy of a response action when the executive director determines that a substantial change in the TEFs alters the calculated TEQ in such a way that it results in the actual toxicity of the dioxin and furan mixture not being protective of human health and the environment. The rule also specifies that it is possible that a person might not be required to conduct a response action in the case where a significant change in the TEFs affects the TEQ in such a way that reveals a response action is no longer warranted to protect human health and the environment.
The commission adopts the amendment to §350.76(e)(3) which removes language that establishes the critical soil PCL for residential properties for all three tiers as 1 part per billion (ppb) and for commercial/industrial properties for all three tiers as 5 ppb. The adopted rule specifies that the critical soil PCLs for residential and commercial/industrial properties shall be calculated for a 2,3,7,8-TCDD TEQ according to the equations and rule provisions provided in §350.75.
Final Regulatory Impact Determination
The commission reviewed the rulemaking adoption in light of the regulatory analysis requirements of the Texas Government Code, §2001.0225. The commission determined that the action is not subject to Texas Government Code, §2001.0225, because it does not meet the definition of a "Major environmental rule" as defined in that statute. A "Major environmental rule" is a rule, the specific intent of which is to protect the environment or reduce risks to human health from environmental exposure, and that may adversely affect in a material way the economy, a sector of the economy, productivity, competition, jobs, the environment, or the public health and safety of the state or a sector of the state.
The specific intent of the rulemaking adoption is to adjust TRRP §350.76 methods and measures related to dioxins/furans and dioxin-like PCBs to align with current accepted science. Specifically, the rulemaking adoption revises the dioxin/furan and dioxin-like PCB soil PCLs used for residential and commercial/industrial land use under TRRP and updates TEFs related to dioxins/furans and dioxin-like PCBs contained in §350.76 in light of more recent scientific evaluation, evolving science, and current data. The rulemaking adoption is not expected to adversely affect in a material way the economy, a sector of the economy, productivity, competition, jobs, the environment, or the public health and safety of the state or a sector of the state. Instead, the rulemaking adoption may affect the costs and timeliness of cleanups of those sites where dioxins/furans or dioxin-like PCBs are the subject of investigation or remediation pursuant to TRRP. The adopted amendments do not rise to the level of material modifications, but instead are limited to incorporating modifications to the current regulatory framework based on current science and data regarding dioxins/furans and dioxin-like PCBs. Therefore, the rulemaking adoption does not meet the definition of a major environmental rule.
Furthermore, even if the rulemaking adoption did meet the definition of a major environmental rule, the rulemaking adoption does not meet any of the four applicability requirements listed in Texas Government Code, §2001.0225. Section 2001.0225 applies to a major environmental rule, the result of which is to: exceed a standard set by federal law, unless the rule is specifically required by state law; exceed an express requirement of state law, unless the rule is specifically required by federal law; exceed a requirement of a delegation agreement or contract between the state and an agency or representative of the federal government to implement a state and federal program; or adopt a rule solely under the general powers of the agency instead of under a specific state law. The rulemaking adoption does not meet any of the four applicability requirements listed in Texas Government Code, §2001.0225.
First, the rulemaking does not exceed a standard set by federal law. Second, the rulemaking does not adopt requirements that are more stringent than existing state laws. Third, the rulemaking adoption does not exceed a requirement of a delegation agreement or contract between the state and an agency or representative of the federal government, where the delegation agreement or contract is to implement a state and federal program. Fourth, this rulemaking does not adopt a rule solely under the general powers of the agency. Rather, sections of the TWC, Chapter 26, and Texas Health & Safety Code, Chapter 361, authorize this rulemaking, which are cited in the Statutory Authority section of this preamble.
The commission invited public comment regarding the draft regulatory impact analysis determination during the public comment period. The TCEQ did not receive any comments on the regulatory impact analysis.
Takings Impact Assessment
The commission evaluated the rulemaking adoption and performed analysis of whether the adopted rules constitute a taking under Texas Government Code, Chapter 2007. The specific purpose of the adopted rules is to adjust TRRP §350.76 methods and measures related to dioxins/furans and dioxin-like PCBs to align with current accepted science. The rulemaking adoption substantially advances this stated purpose by revising the soil PCLs and updating the TEFs related to these constituents.
Promulgation and enforcement of this rulemaking adoption is neither a statutory nor a constitutional taking of private real property. Specifically, the subject adopted regulations do not affect a landowner's rights in private real property because this rulemaking does not burden (constitutionally) nor restrict or limit the owner's right to property and reduce its value by 25% or more beyond that which would otherwise exist in the absence of the regulations. In other words, the rulemaking adoption does not burden private real property because it incorporates modifications to the current regulatory framework based on current science and data regarding dioxins/furans and dioxin-like PCBs.
Consistency with the Coastal Management Program
This rulemaking is not applicable to the Coastal Management Program.
Public Comment
The commission offered a public hearing on September 30, 2024. The comment period closed on October 1, 2024 and no public comments were received.
Statutory Authority
The rule change is adopted under the authority of Texas Water Code (TWC), §5.102, concerning general powers of the commission; TWC, §5.103, which authorizes the commission to adopt any rules necessary to carry out its power and duties; TWC, §5.105, which authorizes the commission to establish and approve all general policy of the commission by rule; TWC, §26.011, which authorizes the commission to administer the provisions of TWC, Chapter 26; TWC, §26.039, which states that activities which are inherently or potentially capable of causing or resulting in the spillage or accidental discharge of waste or other substances and which pose serious or significant threats of pollution are subject to reasonable rules establishing safety and preventative measures which the commission may adopt or issue; TWC, §26.121, which prohibits persons from discharging wastes into or adjacent to any water in the state unless authorized to do so and prohibits persons from engaging in any other activity which causes pollution of any water in the state; TWC, §§26.262 and 26.264, which state it is the policy of this state to prevent the spill or discharge of hazardous substances into the waters in the state and authorizes the commission to issue rules to carry out the policy; TWC, §§26.341 and 26.345, which state it is the policy of this state to maintain and protect quality of groundwater and surface water resources from pollution from certain substances in underground and above-ground storage tanks and authorizes the commission to adopt rules to carry out the policy; TWC, §26.401, which states that it is the policy of this state that discharges of pollutants, disposal of wastes, or other activities subject to state regulation be conducted in a manner to maintain and not impair groundwater uses or pose a public health hazard, and that groundwater quality be restored if feasible; Texas Health & Safety Code (THSC), §§361.017 and 361.024, which establish the commission's jurisdiction over all aspects of the management of industrial solid waste and hazardous municipal waste with all power necessary or convenient to carry out the responsibilities of that jurisdiction and authorizes the commission to adopt rules; and THSC, Chapter 361, Subchapter F, which authorizes the commission to identify, assess, and remediate facilities that may constitute an imminent and substantial endangerment to public health and safety or the environment due to a release or threatened release of hazardous substances into the environment.
The adopted rules implement TWC, Chapter 26, and THSC, Chapter 361.
The agency certifies that legal counsel has reviewed the adoption and found it to be a valid exercise of the agency's legal authority.
Filed with the Office of the Secretary of State on January 17, 2025.
TRD-202500152
Charmaine Backens
Deputy Director, Environmental Law Division
Texas Commission on Environmental Quality
Effective date: February 6, 2025
Proposal publication date: August 30, 2024
For further information, please call: (512) 239-6087