2024-25070. Reconsideration of the Dust-Lead Hazard Standards and Dust-Lead Post-Abatement Clearance Levels

Table 1—Percent Exceedance Values for Zero Dust-Lead, Age: 2-Year-Old (30 Months)

Approach	Floor (µg/ft²)	Sill (µg/ft²)	Probability
			Total BLL >3.5 µg/dL (%)	Total BLL >5 µg/dL (%)	Dust only BLL >1 µg/dL (%)	Dust only BLL >2.5 µg/dL (%)
Zero 1	0	0	5.7	2.2	0.0	0.0
1  The exceedance values for zero dust-lead are provided for comparison with the DLRL candidates; it is not a candidate value and is for informational purposes only.

In 2011, EPA's Scientific Advisory Board (SAB) and in 2012 the Children's Health Protection Advisory Committee (CHPAC) both expressed support for an incremental BLL approach that focuses on dust-lead exposure only. In 2011 SAB reviewed EPA's Approach for Developing Lead Dust Hazard Standards for Residences (November 2010 Draft) and Approach for Developing Lead Dust Hazard Standards for Public and Commercial Buildings (November 2010 Draft) and provided feedback that there are several key advantages to the incremental approach ( e.g., reducing uncertainty from estimating exposures from other media) and provided that a change in BLL “of 1 or 2 μg/dL at the 90th percentile” could be an example of a target risk level. Similarly, CHPAC expressed support for using an incremental approach and preferred levels such that an adverse change in BLL is “no greater than 1 or 2.5 µg/dL” (Ref. 68).

As a result, EPA also estimated what dust-lead levels (considering only the dust-lead component in the multi-media exposure modeling) would result in incremental BLL change ranging between 1 and 2.5 μg/dL based on exposure assumptions described in the TSD (Ref. 12).

For this reconsideration rulemaking the Agency considered the estimated total/aggregate IQ change ( i.e., the estimated total or aggregate IQ change from modeled BLL including all modeled sources of lead exposure) at age six and compared it to a threshold of 1 to 2 points. IQ changes due to background exposures to lead in other media ( e.g., soil, diet, water, and air) are estimated to already have a 48.7% probability to exceed 2 points for children in target housing without also considering additional dust-lead exposure (Ref. 12).

Table 2—Percent Exceedance Values for Zero Dust-Lead, Age: 6-Year-Old (72 Months)

Approach	Floor (µg/ft²)	Sill (µg/ft²)	Probability
			Total IQ decrement >1pt (%)	Total IQ decrement >2pt (%)	Dust only IQ decrement >1pt (%)	Dust only IQ decrement >2pt (%)
Zero 1	0	0	88.9	48.7	0.0	0.0
1  The exceedance values for zero dust-lead are provided for comparison with the DLRL candidates; it is not a candidate value and is for informational purposes only.

In addition to total/aggregate IQ change, EPA determined BLLs that were estimated to result in an incremental loss of 1 to 2 IQ points from exposure to only dust-lead ( i.e., exclusive of lead in other media such as soil, diet, water, and air). This metric is explicitly health-based, in that it is an estimated health effect. There is EPA precedence for using the metric of an incremental change in IQ with a range of values of 1 to 2 points to inform national standards decisions. This includes the 2008 and 2016 decisions on the primary national ambient air quality standard (NAAQS) for lead, which was informed by consideration of air-related IQ decrement estimates based on an evidence-based framework, with a focus on the at-risk subpopulation of children living near sources who are likely to be ( print page 89432) most highly exposed to air-related lead (Ref. 69). In their review of various technical documents supporting both the 2008 and 2016 NAAQS reviews, the Clean Air Scientific Advisory Committee (CASAC) supported using an incremental 1-to-2-point IQ decrement approach for consideration during development of the air standard (Refs. 69 and 70).

When modeling the “any reportable level” approach in the TSD to compare to these health and exposure metrics of interest (as discussed previously), EPA used estimated dust-lead loadings ranging from 0.8 to 2.0 µg/ft² for floors and 0.8 to 4.3 µg/ft² for window sills. These are estimated values for an any reportable level DLRL paired with both the proposed DLAL (3 μg/ft² , 20 μg/ft² , and 25 μg/ft² for floors, window sills, and window troughs respectively) and the proposed alternative DLAL (5 μg/ft² , 40 μg/ft² , and 100 μg/ft² for floors, window sills and window troughs respectively, which is being finalized in this rulemaking). These estimated dust-lead loadings account for the lower reporting thresholds that EPA estimates laboratories will realistically attain under this rule. EPA collected information on real-world laboratory reporting limits from stakeholder outreach conversations. These any reportable level values listed in this unit are based on the average of reporting limits (which can vary across laboratories) that currently report numeric dust wipe loadings at levels 80% of the DLAL options. For the details of these calculations, see Section 2.4.6 of the EA (Ref. 10). Once again, EPA also used a hypothetical dust-lead loading value of zero, for comparison purposes only, to better understand the estimated impact that lead exposure from other matrices is expected to have on a young child without any dust-lead exposure.

The dust-lead reportable level will be used as a tool to identify when there are LBP hazards, particularly dust-lead hazards present, and to disclose those hazards to the individuals who requested the work. EPA's analysis for the final DLRL (any reportable level partnered with the final DLAL of 5 μg/ft2 and 40 μg/ft2 for floors and window sills) shows that after implementation of this standard, young children in target housing are estimated to have a 9.8% probability of exceeding an incremental BLL of 1 μg/dL (tables 12-2 and 12-3 in the TSD). In contrast, under the 2019 DLHS of 10 μg/ft2 and 100 μg/ft2, such children would have a 36.7% probability of exceeding that BLL.

When evaluating the final DLRL of any reportable level partnered with the final DLAL of 5 μg/ft² and 40 μg/ft² for floors and window sills by its impact on the metric of total BLL, the modeling includes exposure from other media such as soil, diet, water, and air. Importantly, even at zero dust-lead, 2-year-old children in target housing are estimated to have a 5.7% probability of exceeding the BLRV given the impact of these other exposures. This is because children who reside in target housing (built before 1978) have higher exposures to lead in soil and water relative to the overall population of US children (Ref. 71). However, the TSD modeling results did show that for any reportable level approach partnered with the final DLAL, there was a 10% probability of exposed 2-year-old children's BLL exceeding the CDC BLRV given their likely exposures to other sources of lead, an increase of 4.3% from the 5.7% probability at zero dust-lead and a reduction from the 2019 DLHS levels of 18%.

Table 3—Percent Exceedance Values for DLRL Candidates, Age: 2-Year-Old (30 Months)

Approach	Floor (µg/ft²)	Sill (µg/ft²)	Probability
			Total BLL >3.5 µg/dL (%)	Total BLL >5 µg/dL (%)	Dust only BLL >1 µg/dL (%)	Dust only BLL >2.5 µg/dL (%)
Zero 1	0	0	5.7	2.2	0.0	0.0
ARL With 3/20 DLAL	0.8	0.8	8.4	3.0	4.2	0.2
ARL With 5/40 DLAL	2.0	4.3	10.0	3.8	9.8	0.9
Current Standard	10	100	18.0	7.5	36.7	6.5
1  The exceedance values for zero dust-lead are provided for comparison with the DLRL candidates; it is not a candidate value and is for informational purposes only.

DLRL candidates with the any reportable level approach are also estimated to be associated with a considerable reduction in the percent exceedance values for the lowest IQ decrements when compared with the current DLHS of 10/100 μg/ft² for floors and window sills. Any reportable level partnered with the final DLAL option (5 μg/ft² , 40 μg/ft² ) is estimated to have an 8.4% probability of greater than 2 points of IQ decrement associated with dust-exposure, keeping the percentage of exceedance of 2 points of IQ decrement below 10% probability compared with the previous 2019 DLHS of 37.9%.

Table 4—Percent Exceedance Values for DLHS Candidates, Age: 6-Year-Old (72 Months)

Approach	Floor (µg/ft²)	Sill (µg/ft²)	Probability
			Total IQ decrement >1pt (%)	Total IQ decrement >2pt (%)	Dust only IQ decrement >1pt (%)	Dust only IQ decrement >2pt (%)
Zero 1	0	0	88.9	48.7	0.0	0.0
ARL With 3/20 DLAL	0.8	0.8	96.4	71.0	20.3	2.7
ARL With 5/40 DLAL	2.0	4.3	97.7	78.0	39.2	8.4
Current Standard	10	100	99.4	90.3	75.8	37.9
1  The exceedance values for zero dust-lead are provided for comparison with the DLRL candidates; it is not a candidate value and is for informational purposes only.

( print page 89433)

d. Public Comment Input

EPA received a number of comments during the public comment period that supported the proposed DLHS approach (described as DLRL moving forward) of “any reportable level” based on their view that there is no safe level of lead exposure. Multiple commenters also emphasized the dangers of lead exposure and were supportive as the DLRL will make the public and the regulated community aware of the risk lead dust may pose. Comments were also received expressing a lack of support for any reportable level, highlighting several primary concerns: that this approach would lead to larger public health impacts, create housing instability, encompass background levels of lead or lead sources that are not from lead-based paint, that the level would vary or be inconsistent from laboratory to laboratory, concerns over liability, and the impacts that an increase in costs would have.

EPA's responsibility when revising the DLRL (which is being done in accordance with the May 2021 Court Opinion and EPA's statutory authority) is to identify “any condition that causes exposure to lead from lead-contaminated dust . . . that would result in adverse human health effects” (emphasis added) (15 U.S.C. 2681(10)). These health-only considerations do not include broader public health concerns and are specifically focused on the health impacts of dust-lead exposure, without consideration of housing instability, source of the lead in the dust, cost, etc. In 2019 when EPA originally revised the DLHS, the Agency did so based on other factors such as risk management, consistency across the U.S. government, and laboratory capacity and capability, among other reasons. The 2021 Court opinion clearly explained that EPA must reconsider the 2019 DLHS and do so using health-only factors.

Firstly, EPA agrees with public commenters about the importance of the availability of affordable housing in the United States and wants to highlight actions this Administration has taken on this issue, such as the May 2022 Housing Supply Action Plan which was last updated in July 2023 with actions to further lower housing costs and boost supply (Refs. 72 and 73). Access to secure housing is an important social determinant of health (Ref. 74). Research finds negative health effects resulting from three key mechanisms of housing insecurity: lack of housing affordability leading to stress and material deprivation (Refs. 75, 76, 77 and 78), lack of housing stability (Refs. 79, 80, 81, 82 and 83), and lack of safe and adequate housing (Refs. 84, 85, 86, 87 and 88). EPA does not want to negatively impact the availability of housing stock with this final rulemaking nor disincentivize participation in any Federal programs and plans to work closely with HUD to try to help mitigate any such consequences. See Unit V.B. for more information on the implications of this rulemaking on HUD programs.

Secondly, EPA acknowledges that lead is naturally occurring and that it is impossible to entirely remove lead from nature. EPA acknowledges that background concentrations of dust-lead could be higher than any reportable level as analyzed by an NLLAP-recognized laboratory, depending on the sensitivity of the dust-wipe sampling technology being used and the background levels themselves. However, in EPA's 2001 LBP Hazards Rule establishing the original dust-lead standards, including the DLHS and DLCL (described as DLRL and DLAL moving forward), EPA explained that the Agency would not exclude from coverage under TSCA Title IV certain dust or soil based on its lead source due to both statutory and technical reasons. The 2001 Response to Comment Document (that accompanies the 2001 LBP Hazards Rule) rightly pointed out that the definitions of “lead-contaminated soil” and “lead-contaminated dust” from TSCA section 401 do not include mention of lead-paint or any reference to paint as the source of lead in dust or soil. Additionally, the definition of a “lead-based paint hazard” lists exposure to lead from lead-contaminated dust and soil as sources of lead contamination separate from—and not explicitly linked to—lead-contaminated paint. The 2001 Response to Comment Document continues that in addition to soil, paint and dust being defined separately and distinctly in the statute, TSCA section 403 directs EPA to “promulgate regulations which shall identify, for the purposes of [TSCA Title IV] and the Residential Lead-Based Paint Hazard Reduction Act of 1992, lead-based paint hazards, lead-contaminated dust, and lead-contaminated soil” (15 U.S.C. 2683). If the definitions for lead-contaminated dust and soil were meant to include only lead from paint, it would not be necessary to list them separately in TSCA section 403. EPA ultimately concluded, based on the “breadth of the definition for lead-contaminated dust and soil taken together with the structures of both Title X and TSCA demonstrate that the lead source in lead-contaminated dust and soil covered by these statutes is not limited to lead from paint.” For the full discussion, see the 2001 response to comments document (Ref. 89).

Separately, EPA also pointed out in the 2001 response to comments document the complexity of identifying a method for distinguishing the risks based on different types of lead ( i.e., from different sources). It is not possible to determine easily and with good precision what element of lead in dust or soil is from what specific source or building component. EPA concluded at the time that “there is a distinct absence of a scientific method to determine conclusively that the source of lead in dust or soil is not paint on a routine basis.” EPA believes that this conclusion has not changed, and while there are some studies that involve stable isotope ratios (see 2001 response to comments document for more information), those are not a viable solution for the LBP activities program which includes numerous properties that fall under the definition of target housing and COFs, with risk assessments and testing happening across the United States on a routine basis.

Note that the U.S. Court of Appeals for the District of Columbia Circuit upheld this interpretation pertaining to source apportionment in 2002 in Nat'l Multi Housing Council v. EPA, 292 F.3d 232 (D.C. Cir. 2002). Based on the epidemiological evidence available, EPA observed in the 2013 and 2024 Integrated Science Assessments that there is no evidence of a threshold below which there are no harmful effects on cognition from lead exposure, (Refs. 5 and 56), and that conclusion is not impacted by the source of that lead exposure. EPA is also unaware of any information that points to different health effects based on different types of dust-lead ( i.e., dust-lead from soil vs. dust-lead from household paint).

Thirdly, EPA agrees with the commenters that the final DLRL (previously referred to as DLHS) will potentially vary from laboratory to laboratory. EPA sees this as a strength of the final DLRL: that there is room for improvement and the possibility of getting as low as reliably reportable depending on the sensitivity of the technology, which in turn allows the regulated community to be able to disclose lower levels. In addition, EPA sets the minimum standards laboratories need to meet, outlined in the latest LQSR version 4.0. Therefore, EPA feels the potential for variability that the commenters are raising is limited and any variability would be below the 80% ( print page 89434) of the lowest action level for dust wipe samples per specific surface area ( i.e., equal to or less than 4 µg/ft² for floors, 32 µg/ft² for window sills and 80 µg/ft² for troughs). This will also reduce the need to revise the DLRL, unless there is a compelling reason to, such as a threshold for adverse effects being identified. EPA also notes that it has previously adopted and continues to apply an analogous concept in the disclosure program (40 CFR part 745, subpart F and 24 CFR part 35, subpart A), where disclosable records and reports have included any information regarding LBP or LBP hazards, including dust-lead levels below the DLHS (described as DLRL moving forward). As laboratory testing protocols have improved, so has the quality of the information in the records and reports based on such testing, which are ultimately provided to the home/building owner or lessee.

EPA points the regulated community to other changes being finalized in the rulemaking, such as the definition of abatement and the nomenclature change, which will adjust the terminology used for the standards. EPA is finalizing a change in the definition of abatement that results in the recommendation for action being shifted to the DLAL (rather than the DLHS, described as DLRL moving forward, as has been the case historically). The DLAL is being finalized as 5 µg/ft² , 40 µg/ft² and 100 µg/ft² for floors, window sills, and window troughs. EPA also recommends that all local, Federal and authorized programs make similar changes, to change their trigger for recommending action, for the same reasons EPA has explained that this rulemaking adopts such changes. EPA believes this change will also alleviate some of the concerns surrounding laboratory inconsistency if the recommendation for action hinges off of the DLAL rather than the DLRL. See Unit IV.A. and Unit IV.E. for more information on these amendments.

Additionally, due to feedback from public comments (see Section 5 of the response to comments document that accompanies this final rule for more information), EPA is also finalizing changes to the nomenclature of DLHS and DLCL, to dust-lead reportable level and dust-lead action level (abbreviated DLRL and DLAL). EPA believes these revisions will better communicate to the public the purpose of the standards and to reduce confusion. EPA believes these changes will also help address some of the commenters' concerns about potential liability for LBP professionals or landlords from allowing dust-lead hazards to remain.

A more comprehensive version of EPA's responses on all of these issues can be found in the response to comments document that accompanies this rulemaking (Ref. 38).

2. Other Approaches EPA Considered in the Proposed Rule

EPA considered two other approaches for revising the DLHS (described as DLRL moving forward): a “numeric standard” approach and a “post-1977 background” approach. Both approaches were discussed in depth in the proposed rule, which also included requests for comment. All three approaches ( i.e., any reportable level, numeric standard, and post-1977 background) would take different analytical paths to revising the DLRL based only on health considerations. EPA is finalizing any reportable level, see Unit IV.B.1. for more information; however, the other two approaches EPA considered are summarized briefly elsewhere in this unit (Unit.IV.B.2.). See the 2023 Proposed Rule for more detailed information (Ref. 55).

The “numeric standard” approach would have been based on the probability of exceedance of one or more IQ or BLL metrics as determined by the Agency, meaning that the Agency would establish a DLRL with a rationale based solely on the interpretation of the TSD results and using a selected metric. To do this, the Agency would need to establish a health or exposure metric of interest ( i.e., target BLL or IQ change) that would be acceptably protective of human health, such as the metrics used in the TSD and described in Unit IV.B.1.c. Within the TSD and for the 2023 Proposed Rule, EPA evaluated several numeric DLRL candidates that the Agency thought were appropriate given the health and exposure metrics of interest and the uncertainty of the model at low loading values. The numeric DLRL candidates discussed in the proposed rule were 1/10 μg/ft² ( i.e., 1 μg/ft² for floors and 10 μg/ft² for sills), 2/20 μg/ft² , 3/30 μg/ft² , and 5/40 μg/ft² and those values were compared with the specified BLL and IQ metrics to estimate the probability of exceeding the BLL or IQ targets.

In 2001 and 2019, EPA expressed the challenges of meeting the statutory criterion for defining a LBP hazard (15 U.S.C. 2681(10)) because it requires EPA to choose a cutoff for when unacceptable risk exists. EPA noted in 2001, even if the science and environmental-lead prevalence data were perfect, there would likely be no agreement on the level, or certainty, of risk that is envisioned in the phrase “would result in adverse human health effects.” Thus, EPA explained that it “would not be appropriate to base a [LBP] hazard standard on any specific probability of exceeding any specific [BLL].” (Refs. 2 and 20).

For this numeric approach the Agency would need to establish a health or exposure metric of interest ( i.e., target BLL or IQ change) that would be acceptably protective of human health. Under this numeric standard approach, EPA planned to use the threshold of 5% probability of exceedance for a child from the population of interest ( i.e., young children living in pre-1978 housing and COFs). This is similar to the 1 to 5% probability that was used in 2001 for the lowest DLHS candidate (Ref. 20). However, EPA ultimately continues to agree with the challenges that were highlighted in 2001 and 2019, and the complexity with identifying a cutoff of risk or specific IQ/BLL metrics of interest that would be acceptable for purposes of setting the DLRL. Accordingly, EPA continues to favor the “any reportable level” approach.

EPA also considered and requested comment on the “post-1977” background approach that would use the average background dust-lead levels of housing built in 1978 and beyond as the DLRL. This approach would align target housing dust-lead levels with dust-lead levels in housing built after lead-based paint was banned. In 1978, the CPSC banned lead in paint and similar surface-coating materials for consumer use in excess of 0.06% and revised the level in 2009 to 0.009% following the Consumer Product Safety Improvement Act of 2008 (Pub. L. 110-314). As a result of CPSC's 1978 lead paint ban, the focus of EPA's LBP activities program is target housing, which includes most pre-1978 housing and COFs. This approach would result in lowering the DLRL to the dust-lead background levels of housing built after 1977 (known as “post-1977 background”), which are presumably not from paint on the house in question containing more than 0.06% lead.

Post-1977 background dust-lead values were calculated from a weighted geometric mean of the dust-lead loadings from the American Healthy Homes Survey II and were found to be 0.2 µg/ft² for floors and 0.8 µg/ft² for window sills (Refs. 10 and 53). Setting the DLRL at the post-1977 background dust-lead levels would allow EPA to focus on dust-lead hazards above what is expected in housing without LBP ( i.e., after CPSC established a maximum level of lead in paint for consumer products, including home paints). Establishing DLRL for target housing and COFs in this way, using post-1977 background ( print page 89435) dust-lead levels, would address disparities in the dust-lead levels that children in target housing may be exposed to and the corresponding disparate health risks. This approach would also align with the focus of Title X on lead hazards in housing constructed before 1978. However, there are questions about whether the post-1977 background approach would directly address the 2021 Court Opinion as the “any reportable level” approach does.

See the 2023 Proposed Rule for more detailed information about these two approaches, including a description of their estimated modeling results, such as BLL/IQ decrement impacts (Ref. 55). EPA did not receive significant public comment for either of these approaches and given the 2021 Court Opinion remanding the DLHS for reconsideration based only on health factors, the results of the analysis in the TSD, and the lack of a discernible threshold in the evidence for the association of blood lead with harmful effects on cognition in young children, EPA is finalizing revisions to the 2019 DLHS to any reportable level of lead analyzed by an NLLAP-recognized laboratory, as proposed.

C. Dust-Lead Action Level Approach

TSCA Title IV granted EPA the authority to regulate LBP activities, and to take into account reliability, effectiveness, and safety (15 U.S.C. 2682(a)(1)) when setting those regulations (including the DLAL). While considering those three criteria, the 2001 LBP Hazards Rule modified the work practice standards to include DLCL (described as DLAL moving forward), which “are used to evaluate the effectiveness of cleaning following an abatement” (Ref. 20). In both the 2001 LBP Hazards Rule and the 2021 Final Rule, the DLCL were finalized as the same value as the DLHS (described as DLRL moving forward) for floors and window sills. When originally established, EPA considered the DLCL in the broader context of Title X, and selected DLCL that were compatible with a “workable framework for lead-based paint hazard evaluation and reduction.” EPA chose DLCL that were consistent with the DLHS in part to ensure they were “as easy as possible to understand and implement” (Ref. 66). At that time EPA established the DLCL and the DLHS at 40 μg/ft² and 250 μg/ft² for floors and window sills, with a separate DLCL of 400 μg/ft² for troughs.

In 2021 the DLCL set by EPA continued to mirror the DLHS as it had done historically, as the Agency explained that it wanted to update the DLCL to achievable levels that would demonstrate elimination of dust-lead hazards under the 2019 DLHS of 10 μg/ft² for floors and 100 μg/ft² for window sills. The 2021 updates to the DLCL restored consistency between the DLCL and DLHS, which had been lowered in 2019 without a corresponding amendment to the DLCL. Previous public comments received on the 2018 DLHS proposal and 2020 DLCL proposal favored lowering the DLCL to be consistent with the DLHS (Refs. 90 and 91). As a result, in 2021 EPA finalized DLCL of 10 μg/ft² for floors and 100 μg/ft² for window sills (the same levels as the DLHS), and “EPA considered the achievability of these levels, how the lower dust-lead loadings can be reliably detected by laboratories, the effectiveness of these levels, and consistency with the revised 2019 standards and across the Federal Government” (Ref. 3).

The 2021 Court Opinion affirmed that “TSCA [Title] IV gives the EPA latitude to consider `reliability, effectiveness, and safety'” when promulgating regulations “[w]ith respect to implementation, including abatement.” A Cmty. Voice, 997 F.3d at 995 (Ref. 9). This would include the DLCL/DLAL as they represent part of post-abatement work practices. The Court continued by emphasizing that this gives EPA more discretion when setting the DLCL because they are relevant to the implementation of remedial measures, rather than the identification of a hazard ( i.e., DLHS/DLRL). The Court analogized this dichotomy to other environmental statutory schemes (see also Unit IV.B.1.b. for EPA's discussion of the SDWA). The Court also held that the DLCL and DLHS are directly related and must be reconsidered together. Yet the Court recognized the difference in statutory authority and considerations (see Unit IV.B. for more information on DLRL, previously referred to as DLHS).

In accordance with the 2021 Court Opinion, EPA is finalizing revisions to the DLAL (previously referred to as the DLCL) in the same proceeding as the reconsideration of the 2019 DLHS (described as DLRL moving forward). Given the Court's direction for the considerations for how to revise the DLHS and DLCL and similar to what was proposed in 2023, EPA is finalizing dust-lead action levels that are decoupled from the dust-lead reportable levels (see Unit I.B. and C. for more background on decoupling). EPA evaluated the 2021 DLCL in accordance with the statute and is finalizing revisions to lower the levels to the alternative option that was proposed in 2023, from 10 µg/ft² , 100 µg/ft² and 400 µg/ft² for floors, window sills, and troughs, respectively, to 5 µg/ft² , 40 µg/ft² , and 100 µg/ft² and is finalizing a change in the terminology to DLAL.

1. Rationale for Selecting the Final DLAL

EPA is finalizing the DLAL given the statutory criteria of reliability, effectiveness, and safety, based on consideration of HUD's Lead Hazard Control Clearance Survey (LHCCS), an evaluation of laboratory capabilities and capacity, the potential for risk reduction compared to the 2021 DLCL by lowering exposure to dust-lead, resource considerations and the Agency's careful review of the public comments received on the proposal. EPA chose 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² for floors, window sills and window troughs, respectively, as the DLAL based on these consideration as well as high confidence that these standards can be successfully implemented, as shown by the use of these clearance levels currently in NYC. Another consideration supporting the choice of these DLAL is to avoid potentially spreading the limited resources for LBP hazard mitigation so broadly that they may be diverted from scenarios that present the greatest risk.

a. Lead Hazard Control Clearance Survey.

EPA collaborated with HUD to develop the 2015 LHCCS. The survey aimed to examine whether HUD's Office of Lead Hazard Control and Healthy Homes (OLHCHH) Lead Hazard Control (LHC) grantees could achieve DLCL (described as DLAL moving forward) below the standards in place at that time ( i.e., below 40 µg/ft² , 250 µg/ft² and 400 µg/ft² for floors, window sills and troughs, respectively). LHC work performed by the grantees must be conducted by LBP certified individuals. Since most of the LHC grantees use commercial firms in their area, HUD OLHCHH believes that the grantees are conducting a large percentage of these activities and are therefore representative of the regulated community.

98 LHC grantees completed the 2015 survey, giving HUD information from housing units in which lead hazard control activities took place from 2010 through 2012, for a total dataset of 1,552 housing units including 7,211 floor samples and 4,893 window sill samples (Ref. 54). The data were analyzed to determine the percentage of samples cleared at or below specific values. Numerical modeling was performed to estimate loadings that fell below laboratory detection limits. For more information on how that analysis was ( print page 89436) conducted please see appendix D of the EA (Ref. 10). Since the 2015 LHCCS report was published, to the Agency's knowledge, there has not been any data or source of information of this magnitude in terms of clearance samples alongside the details of the process, including the number of tests performed (with results) and the type of additional work or cleaning performed. EPA found this 2015 LHCCS report still relevant and recent enough to provide meaningful input to inform this reconsideration rulemaking.

EPA's analysis of the LHCCS data indicates that 72% of samples from 2010 to 2012 showed dust-lead levels at or below 5 μg/ft² for floors, 88% were at or below 40 μg/ft² for window sills, and 93% were at or below 100 μg/ft² for window troughs. As a result, EPA believes that the final DLAL of 5 µg/ft² for floors, 40 µg/ft² for window sills and 100 µg/ft² for troughs are achievable by LBP professionals, especially since the survey respondents were only required to achieve clearance below the 2001 DLCL at that time (40 µg/ft² for floors, 250 µg/ft² window sills, and 400 μg/ft² for window troughs). It is possible that the percentage of samples achieving clearance may be even higher today, due to the 2021 revision of the DLCL to 10 µg/ft² for floors and 100 µg/ft² for window sills, meaning clearance has had to be achieved at these lower levels or below, since that time. As a result, EPA has high confidence that the 5 µg/ft² , 40 µg/ft² , and 100 µg/ft² for floors, window sills, and window troughs DLAL option is achievable by LBP professionals, considering reliability and effectiveness.

b. Laboratory Capabilities for DLAL

In order to better understand how laboratory capabilities would be impacted by the proposed DLAL (previously referred to as DLCL) of 3 μg/ft² , 20 μg/ft² , and 25 μg/ft² for floors, window sills and troughs, respectively, and the final DLAL of 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² , EPA spoke with eighteen NLLAP-recognized laboratories, nine prior to the 2023 Proposed Rule and nine after the public comment period was complete (Refs. 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108 and 109). EPA wanted to collect additional information from NLLAP-recognized laboratories about their dust-wipe programs, especially given that a non-static DLRL would shift the LQSR “action level” to the DLAL (see Unit IV.B.1.a. for more information). As explained in the proposal, EPA was interested in information from laboratories who had high dust wipe testing capacity and laboratories that had both a flame atomic absorption spectroscopy (FAAS) and the more sensitive laboratory instruments such as inductively coupled plasma atomic emission spectroscopy (ICP-AES) (also referred to as inductively coupled plasma optical emission spectroscopy or ICP-OES) or an inductively coupled plasma mass spectroscopy (ICP-MS). The Agency wanted additional background on ICP instruments and their use for dust wipe testing in general. After the public comment period, EPA wanted to continue building on the outreach that had been previously performed and further refine the Agency's understanding of the threshold for FAAS technology in terms of a lower limit of sensitivity by meeting with nine additional laboratories (eighteen total) and physically touring one location (Ref. 101, 102, 103, 104, 105, 106, 107, 108 and 109). Among the laboratories EPA spoke to in 2022, 2023 and 2024, 14 were accredited to use FAAS, 10 were accredited to use ICP-AES, and 2 were accredited to use ICP-MS to analyze dust wipe samples for lead, some being accredited for multiple types of technology. Seventeen of the eighteen laboratories provide commercial testing services, four of which are among the largest U.S. lead laboratories by dust wipe test volume. For additional details about the laboratory capabilities, see Section 2.4 in the EA that accompanies this rulemaking (Ref. 10).

FAAS has been the most popular choice for lead dust wipe testing for some time due in part to its low purchase price and operating cost, speed, and ease of use. Over two-thirds of laboratories recognized under the NLLAP for lead dust wipe testing currently use FAAS, and over half of these NLLAP laboratories rely solely on FAAS (Ref. 10). The laboratories using ICP-AES for dust-wipes tested an order of magnitude fewer dust-wipe samples than laboratories using FAAS. Some of the laboratories accredited for both types of instruments only use their ICP instrument for wipes being analyzed for multiple metals for industrial hygiene analyses or analysis of air or water samples instead of for dust-wipes related to EPA's lead-based paint activities rule (Refs. 97, 101, 104, 107, 108). One laboratory that uses both FAAS and ICP-AES indicated that it used FAAS for 95% of the samples tested and ICP-AES for only 5% (Ref. 98). Another laboratory that uses both FAAS and ICP-AES stated that it used the ICP-AES instrument to test approximately 20 dust-wipes per year, out of 34,000 to 36,000 lead dust-wipes that it analyzes each year (Ref. 104).

The information received from the laboratory outreach that was performed in preparation for the proposed rule indicated that if finalized as proposed, ICP-AES would likely become the instrument standard for dust wipe testing for lead at the NLLAP laboratories, as FAAS instruments were not reported to consistently meet the quantitation limits associated with the proposed DLCL. ICP-AES instruments can detect lead at lower levels than FAAS instruments, but ICP-AES instruments are more expensive to purchase, have higher operating costs for consumable supplies, require a more experienced technician to operate, and need more time for sample preparation, analysis, and quality control requirements than FAAS instruments. Laboratories raised several concerns about switching to ICP instruments, including the reduction in the throughput rate, the need for multiple instruments and staff to operate them, higher prices, delayed turnaround times, and concerns over maintaining the current sample volume. For example, one laboratory EPA spoke to estimated that they would have to purchase three to six new instruments, hire several highly qualified technicians, and run the laboratory on shifts over 24 hours to meet current demand for dust wipe tests conducted solely by ICP (Ref. 96). Several laboratories questioned whether they would keep dust-wipe testing in their portfolio if EPA finalized the levels from the 2023 Proposed Rule (Refs. 96, 98, 103, 107).

This shift in instrumentation that would have been needed as a result of the clearance levels in the proposed rule would increase both cost per sample as well as turnaround time. Dust wipe testing by ICP-AES is approximately two to four times more expensive per sample than testing by FAAS (Refs. 96, 98, 100, 104, 108). Laboratories also mentioned that a substantial portion of their dust-wipe testing clients request results in one day or less (in some cases in as little as several hours) following a lead hazard reduction activity, so that residents can quickly reoccupy their homes (Refs. 95, 101, 103). Some of the laboratories using FAAS indicated that they offered turnaround times as short as several hours (Refs. 96, 104, 107). Several laboratories doubted the feasibility of providing same-day or next-day turnarounds at sufficient volume should they switch to ICP technology (Refs. 96, 98, 104, 108). Longer turnaround times would delay when individuals who temporarily ( print page 89437) moved out can reoccupy their homes, requiring them to spend more time in temporary accommodations (Ref. 91) which can increase the costs of lead hazard reduction activities, thus potentially reducing the number of abatements and interim control that would be funded.

EPA found that several laboratories forecast that dust-wipe test volumes will continue to grow over the next decade even in the absence of this rule (Refs. 96, 97 and 102). First, a growing proportion of laboratories' dust-wipe testing business comes from landlords who need to comply with municipal housing regulations set by States or localities. Laboratories expect similar regulations to be enacted in the coming years, increasing demand for dust-wipe testing for clearance (Ref. 97). Second, in recent years laboratories have received an increased volume of test samples generated by disaster recovery programs. When there is a natural disaster (such as a major flood) that requires clean-up and re-construction of pre-1978 housing, laboratories can receive an unexpected spike in dust-wipe tests. Laboratories pointed out that the increasing rate of disaster-related demand spikes may overwhelm their capacity if only ICP can be used for dust-wipe testing.

Finally, laboratories also expressed concern that increases in costs for activities such as testing, cleaning, and temporary accommodations due to the dust-lead levels EPA originally proposed would reduce the number of housing units where lead hazards would be addressed, in part because State and local municipalities often have a fixed budget for their housing and health programs (Refs. 96 and 108). The laboratories felt that the 2023 Proposed Rule could have the unintended result of exposing more individuals to elevated dust-lead levels for a longer period of time (Refs. 108 and 109). Given the information gathered via EPA's outreach to laboratories, EPA is concerned that setting action levels too low would deter participation in lead-hazard control programs and activities that require dust-wipe testing or cause a market failure that does not allow the current volume of testing to continue.

EPA is finalizing a DLAL of 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² for floors, window sills and troughs. EPA has increased confidence that, relative to the proposed 2023 DLCL ( i.e., 3 μg/ft² , 20 μg/ft² , and 25 μg/ft² ), laboratories can numerically quantify dust-lead levels of 5 μg/wipe with FAAS technology and attain a quantitation limit of equal to or less than 80% of the final DLAL ( i.e., 4 μg/ft² , 32 μg/ft² , and 80 μg/ft² ) for floors, window sills and troughs. EPA believes that the final DLAL, rather than the proposed 2023 DLCL, partnered with the changes incorporated into LQSR 4.0, allows NLLAP-recognized laboratories to continue using FAAS technology. This would mitigate any unintended reductions in dust wipe capacity ( e.g., throughput time, cost, labor, etc.) due to having to switch to more sensitive technology such as ICP-AES. While some NLLAP-recognized laboratories may opt for more sensitive technologies, EPA does not foresee any concerns reporting to 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² even for those surfaces with a smaller area such as on window sills or troughs if laboratories successfully attain a regulatory limit of 5 μg/ft² .

c. Final DLAL Modeling Results

EPA must understand the estimated health impacts of dust-lead exposure when selecting a DLAL that is reliable, effective, and safe, as well as to help inform the economic analysis. The TSD that accompanies this rule includes an evaluation of dust-lead loadings, specifically the 2021 DLCL of 10 μg/ft² and 100 μg/ft² for floors and window sills, the proposed DLAL of 3 μg/ft² and 20 μg/ft² for floors and window sills and the final DLAL of 5 μg/ft² and 40 μg/ft² for floors and window sills, compared to estimated BLL and IQ decrements. The unique dust-lead contribution to exposure from window troughs has not been distinguished from window sills given the strong correlation between dust-lead loadings on the two surface types, the lack of data on access to window troughs and window sills by children, and the paired impacts in window sills and window troughs from intervention studies addressing lead paint in window trim and casings. Further discussion on exposure to window troughs can be found in the TSD in appendix C. As a result, exposure to window trough dust-lead and resultant benefits from a lowered DLAL for troughs is not calculated separately for this rulemaking. The TSD also describes modeling of dust-lead exposures at the specific DLAL options for window sills and floors only and estimates of both BLLs that were evaluated for children at each age up to age six, including age two (generally, this is the age of greatest modeled exposure), and lead-related reduction in IQ at age six was estimated from the lifetime average BLL (average of BLLs across the period prior to age six). See Unit IV.B.1.c. for more specific information on which BLL and IQ decrements were chosen for comparison, and Unit III. for more details on estimated potential impacts from dust-lead exposures analyzed in the TSD. Tables 5 and 6 represent the percent exceedance of highlighted metrics at dust-lead loadings corresponding to the 2021 DLCL (10 μg/ft² and 100 μg/ft² for floors and window sills), the final DLAL (5 μg/ft² and 40 μg/ft² for floors and window sills) and zero (for comparison purposes only).

The final DLAL of 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² for floors, window sills and troughs represents a 50% or more reduction of dust-lead left on a surface following the completion of an abatement, when compared to the 2021 DLCL (10 μg/ft² , 100 μg/ft² , and 400 μg/ft² ). As a result, DLAL of 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² would be beneficial to maintaining lower children's BLLs and protecting against associated health outcomes such as decreased IQ. The modeling results provided in the TSD show that 2-year-old children in pre-1978 housing exposed to dust-lead loadings of 5 μg/ft² for floors and 40 μg/ft² for window sills would have an estimated 13.9% probability of exceeding a total BLL of 3.5 μg/dL (CDC's BLRV). Total BLL includes exposure from other media such as soil, diet, water, and air; even at zero dust-lead, 2-year-old children would still have a 5.7% probability of exceeding the CDC's BLRV from these other sources. The 13.9% probability of exceeding the BLRV is significantly lower than the 18.0% probability of exceedance of the BLRV when exposed to the current DLCL of 10 μg/ft² for floors and 100 μg/ft² on window sills (see table 5).

When considering dust-lead exposure only (not including other estimated lead exposures from soil, diet, water, and air), 2-year-old children in pre-1978 housing exposed to the final DLAL of 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² would have a 3.2 to 23.0% probability of exceeding a BLL of 1 to 2.5 μg/dL based on the modeled results. The final DLAL is also estimated to be associated with a 22.4% probability of exceeding 2 points of IQ decrement in 6-year-old children. As with total BLL, this is a considerable reduction from the 37.9% chance of exceeding 2 points of IQ decrement for 6-year-old children living in target housing who are exposed the current DLCL (table 6). Overall, the modeling within the TSD indicated that the 5 μg/ft² , 40 μg/ft² , and 100 μg/ft² DLCL for floors, window sills and troughs represents a substantial reduction in risk from the current clearance levels of 10 μg/ft² , 100 μg/ft² , and 400 μg/ft² for floors, window sills, and window troughs. ( print page 89438)

Table 5—Percent Exceedance Values for the Final DLAL Candidate, Age: 2-Year-Old (30 months)

Approach	Floor (μg/ft2 )	Sill (μg/ft2 )	Probability
			Total BLL > 3.5 μg/dL (%)	Total BLL > 5 μg/dL (%)	Dust Only BLL > 1 μg/dL (%)	Dust Only BLL > 2.5 μg/dL (%)
Zero 1	0	0	5.7	2.2	0.0	0.0
5/40 DLAL	5	40	13.9	5.5	23.0	3.2
Current Standard	10	100	18.0	7.5	36.7	6.5
1  The exceedance values for zero dust-lead are provided for comparison with the DLRL candidates; it is not a candidate value and is for informational purposes only.

Table 6—Percent Exceedance Values for the Final DLAL Candidate, Age: 6-Year-Old (72 Months)

Approach	Floor (μg/ft2 )	Sill (μg/ft2 )	Probability
			Total IQ Decrement > 1pt (%)	Total IQ Decrement > 2pt (%)	Dust Only IQ Decrement > 1pt (%)	Dust Only IQ Decrement > 2pt (%)
Zero 1	0	0	88.9	48.7	0.0	0.0
5/40 DLAL	5	40	98.8	85.1	62.7	22.4
Current Standard	10	100	99.4	90.3	75.8	37.9
1  The exceedance values for zero dust-lead are provided for comparison with the DLRL candidates; it is not a candidate value and is for informational purposes only.