SUPPLEMENTARY INFORMATION:

Table of Contents

A. WTC Health Program Statutory Authority

B. Procedures for Evaluating a Petition

C. Petition 048a

D. Evaluation of Scientific Evidence: Findings and Conclusion

E. Administrator's Final Decision on Whether To Propose the Addition of Peripheral Artery Disease to the List

F. Approval To Submit Document to the Office of the Federal Register

A. WTC Health Program Statutory Authority

Title I of the James Zadroga 9/11 Health and Compensation Act of 2010 (Pub. L. 111-347, as amended by Pub. L. 114-113, Pub. L. 116-59, Pub. L. 117-328, Pub. L. 118-31, and Pub. L. 119-75), added Title XXXIII to the Public Health Service (PHS) Act,^[1] establishing the WTC Health Program within the Department of Health and Human Services (HHS). The WTC Health Program provides medical monitoring and treatment benefits for health conditions on the List of WTC-Related Health Conditions (List) ^[2] to eligible firefighters and related personnel, law enforcement officers, and rescue, recovery, and cleanup workers who responded to the September 11, 2001, terrorist attacks in New York City, at the Pentagon, and in Shanksville, Pennsylvania (responders). The Program also provides benefits to eligible persons who were present in the dust or dust cloud on September 11, 2001, or who worked, resided, or attended school, childcare, or adult daycare in the New York City disaster area ^[3] (survivors).

All references to the Administrator of the WTC Health Program (Administrator) in this document mean the Director of the National Institute for Occupational Safety and Health (NIOSH) or his designee.

In accordance with section 3312(a)(6)(B) of the PHS Act, interested parties may petition the Administrator to add a health condition to the List in 42 CFR 88.15. Within 90 days after receipt of a valid petition to add a condition to the List, the Administrator must take one of the following four actions described in section 3312(a)(6)(B) of the PHS Act and ( printed page 58453) § 88.16(a)(2) of the WTC Health Program regulations: (1) Request a recommendation of the WTC Health Program Scientific/Technical Advisory Committee (STAC); (2) publish a proposed rule in the Federal Register to add such health condition; (3) publish in the Federal Register the Administrator's determination not to publish such a proposed rule and the basis for such determination; or (4) publish in the Federal Register a determination that insufficient evidence exists to take action under (1) through (3) above.

More information about the WTC Health Program, including the List and the petition process, is available at www.cdc.gov/​wtc/​.

B. Procedures for Evaluating a Petition

In addition to the regulatory provisions, the WTC Health Program has developed policies to guide the review of submissions and petitions,^[4] as well as the analysis of evidence supporting the potential addition of a non-cancer health condition to the List.^[5]

A valid petition must include sufficient medical basis for the association between the September 11, 2001, terrorist attacks and the health condition to be added. In accordance with WTC Health Program Policy and Procedures for Handling Submissions and Petitions to Add a Health Condition to the List of WTC-Related Health Conditions,^[6] reference to a peer-reviewed, published, epidemiologic study about the health condition among 9/11-exposed populations or clinical case reports of health conditions in WTC responders or survivors may demonstrate the required medical basis.^[7] Studies linking 9/11 agents or hazards ^[8] to the petitioned health condition may also provide sufficient medical basis for a valid petition.^[9] In accordance with 42 CFR 88.16(a)(5), the Administrator is required to consider a new petition for a previously evaluated health condition determined not to qualify for addition to the List only if the new petition presents a new medical basis for the association between 9/11 exposures and the condition to be added. A new medical basis is evidence not previously reviewed by the Administrator.

After the Program has determined that a petition is valid, and in accordance with the Policy and Procedures for Adding Non-Cancer Health Conditions to the List of WTC-Related Health Conditions ( Policy and Procedures), the Administrator directs the WTC Health Program Science Team (Science Team) to conduct a review of the scientific literature. The literature review includes a keyword search of relevant scientific databases intended to identify peer-reviewed, published, epidemiologic studies about the health condition among 9/11-exposed populations.

The Science Team evaluates the scientific quality of each peer-reviewed, published, epidemiologic study of the health condition identified in the literature search using validity indicators described in the Policy and Procedures.^[10] Studies exhibiting sufficient validity indicators have the potential to provide a basis for deciding whether to propose adding the health condition to the List and are considered “high-quality” studies. The Science Team then evaluates the identified high-quality studies, individually and together, to characterize the evidence of a causal association between 9/11 exposures and the health condition. As part of this evaluation, the Science Team considers the Bradford Hill weight of evidence criteria,^[11] study limitations, and whether the studies are representative of the 9/11-exposed population of responders and survivors. After evaluating the totality of the evidence, the Science Team assesses the degree to which the evidence supports a causal association between 9/11 exposures and the health condition and assigns the evidence to one of the following five categories:

Category I —Evidence supports substantial likelihood of causal association

Category II —Evidence supports high likelihood of causal association

Category III —Evidence supports limited likelihood of causal association

Category IV —Evidence does not support causal association

Category V —Evidence is inadequate to determine the likelihood of causal association.

The Science Team provides the outcome of its evaluation to the Administrator. A health condition may be added to the List if peer-reviewed, published, epidemiologic studies provide support that there is a substantial likelihood of a causal association between the health condition and 9/11 exposures (Category I).^[12] If the evaluation of evidence provided in peer-reviewed, published, epidemiologic studies of the health condition in 9/11 populations shows a high, but not substantial, likelihood of a causal association between the 9/11 exposures and the health condition (Category II),^[13] then the Administrator may consider additional highly relevant scientific evidence regarding exposures to 9/11 agents in non-9/11 exposure scenarios. If that additional assessment establishes that there is now sufficient evidence to support the conclusion that a causal association between the 9/11 exposures and the health condition is substantially likely among 9/11-exposed populations (Category I), then the Administrator may propose the addition of the health condition to the List.

C. Petition 048a

On September 3, 2023, the Administrator received a submission (Petition 048a) requesting the addition of several cardiovascular conditions, including “peripheral vascular disease” ( printed page 58454) to the List.^[14] The Administrator understands the term “peripheral vascular disease” to mean the health condition commonly known as “peripheral artery disease” (PAD). The petition's validity was established by references to seven peer-reviewed, published, epidemiologic studies that provided a medical basis for the association between 9/11 exposures and PAD. The referenced studies establishing a medical basis are as follows:

Particulate Matter Air Pollution and Cardiovascular Disease: An Update to the Scientific Statement from the American Heart Association, by Brook et al. [2010],^[15] an updated scientific statement concluding that modest epidemiologic evidence supports a causal relationship between exposure to particulate matter (PM) <2.5 micrometers (µm) in diameter (PM_2.5) and increased PAD morbidity.

Expert Position Paper on Air Pollution and Cardiovascular Disease, by Newby et al. [2015],^[16] a scientific review and consensus document by the European Society of Cardiology that evaluated the evidence linking air pollution (comprising the 9/11 agents PM_2.5 and PM ≤10 µm (PM₁₀), ozone, nitrogen dioxide (NO₂), volatile organic compounds (including benzene), carbon monoxide (CO), and sulfur dioxide (SO₂)) to cardiovascular disease (CVD) outcomes including PAD.

A Joint ERS/ATS Policy Statement: What Constitutes an Adverse Health Effect of Air Pollution? An Analytical Framework, by Thurston et al. [2017],^[17] a joint European Respiratory Society/American Thoracic Society policy statement on what constitutes an adverse health effect of air pollution. It provides an analytical framework for interpreting scientific evidence on the health effects of air pollution for risk management purposes and references to papers that describe increased risks of impaired vascular function—a manifestation of PAD—and increased carotid artery stenosis from PM_2.5 exposure.

Ambient Air Quality and Cardiovascular Health: Translation of Environmental Research for Public Health and Clinical Care, by Cascio and Long [2018],^[18] a non-systematic review on CVD outcomes, including PAD, associated with air pollution. The review reported that residential proximity to major roads is associated with increased PAD risk. Traffic-related air pollution includes several 9/11 agents, e.g., PM_2.5, PM₁₀, nitrogen oxides, sulfur dioxide, and carbon monoxide.

Long-Term Cardiovascular Disease Risk among Firefighters after the World Trade Center Disaster, by Cohen et al. [2019],^[19] a peer-reviewed, published longitudinal cohort study of Fire Department of New York (FDNY) firefighters designed to assess whether 9/11 exposures were associated with elevated CVD risk, including a composite outcome variable. Among firefighters with the composite outcome, very few had PAD, however, the study found positive associations between this composite cardiovascular outcome and 9/11 exposures related to time of arrival and length of response.

Integrated Science Assessment (ISA) for Particulate Matter, by EPA's Center for Public Health and Environmental Assessment [2019],^[20] a detailed integrated science assessment that examined the impact of PM, including PM_2.5, on CVD outcomes including PAD. The assessment summarized several studies that found increased PAD risk associated with PM_2.5 exposure.

Environmental Pollution and Peripheral Artery Disease, by Serra et al. [2021],^[21] provided a review of environmental pollutant exposures associated with PAD. This study provided evidence supporting an association between exposure to PM₁₀ and increased PAD risk.

These studies suggest a potential association between exposure to 9/11 agents and PAD and thus provided sufficient medical basis to consider the submission a valid petition.

D. Evaluation of Scientific Evidence: Findings and Conclusion

In response to Petition 048a and pursuant to the Policy and Procedures, the Administrator of the WTC Health Program directed the Science Team to conduct a systematic search of the scientific literature to identify all peer-reviewed, published, epidemiologic studies of PAD among 9/11-exposed populations. Identified studies were assessed for quality; any studies determined to be high-quality would then be evaluated to determine if they provide evidence to support a likelihood of a causal association between 9/11 exposure and the health condition under consideration. The Science Team provided the Administrator with a paper describing its findings, Evaluation of Scientific Evidence Supporting the Addition of Peripheral Artery Disease to the List of WTC-Related Health Conditions. This evaluation builds on a previous evaluation of atherosclerosis, an antecedent health condition leading to the development of PAD, conducted in response to Petition 012. The current evaluation for Petition 048a is available in the docket for this activity ^[22] and on the Program's website.^[23]

( printed page 58455)

The literature search conducted by the WTC Health Program identified nine peer-reviewed, published, epidemiologic studies of PAD in 9/11-exposed populations (including one study by Mani et al. [2013] that was reviewed in the Petition 012 evaluation). None of the nine identified studies, however, demonstrate sufficient validity indicators to be considered high-quality studies.^[24] Accordingly, the Science Team did not conduct further evaluation of the studies identified in the literature search described above.

Upon review of the evidence available in peer-reviewed, published, epidemiologic studies regarding PAD among 9/11-exposed populations, the Science Team found that there is inadequate evidence to determine a causal association ^[25] between 9/11 exposures and PAD (Category V).

E. Administrator's Final Decision on Whether To Propose the Addition of Peripheral Artery Disease to the List

Pursuant to the PHS Act, sec. 3312(a)(6)(B)(iv) and 42 CFR 88.16(a)(2)(iv), and in accordance with Sec. VIII.B. of the Policy and Procedures, the Administrator has determined that insufficient evidence is available to take further action at this time, including proposing the addition of PAD to the List (pursuant to the PHS Act, sec. 3312(a)(6)(B)(ii) and 42 CFR 88.16(a)(2)(ii)) or publishing a determination not to publish a proposed rule in the Federal Register (pursuant to the PHS Act, sec. 3312(a)(6)(B)(iii) and 42 CFR 88.16(a)(2)(iii)). The Administrator has also determined that requesting a recommendation from the STAC (pursuant to the PHS Act, sec. 3312(a)(6)(B)(i) and 42 CFR 88.16(a)(2)(i)) is unwarranted.

For the reasons discussed above, the request in Petition 048a to add PAD to the List of WTC-Related Health Conditions is denied.

F. Approval To Submit Document to the Office of the Federal Register

The Secretary, HHS, or his designee, the Director, Centers for Disease Control and Prevention (CDC) and Administrator, Agency for Toxic Substances and Disease Registry (ATSDR), authorized the undersigned, the Administrator of the WTC Health Program, to sign and submit the document to the Office of the Federal Register for publication as an official document of the WTC Health Program. Erica Schwartz, MD, MPH, JD, RADM, USPHS (ret), Director, CDC, and Administrator, ATSDR, approved this document for publication on September 8, 2026.

91 FR 58452