About

Dr. Cassandra Thiel is an Assistant Professor at the Robert F. Wagner Graduate School of Public Service with a joint appointment at the NYU Langone School of Medicine in the Department of Population Health. Her research focuses on systematically measuring and analyzing environmental inefficiencies in medical services and built infrastructures to optimize these systems. She utilizes sustainable engineering tools, such as life cycle assessment (LCA) and industrial ecology, to improve hospitals, healthcare delivery, and medical waste streams. Her background includes a PhD in Civil Engineering with an emphasis on Sustainable Healthcare and Green Buildings from the University of Pittsburgh. As a 2014-2015 Fulbright-Nehru Academic and Professional Excellence fellow, she collaborated with ophthalmologists at Aravind Eye Hospitals in India and conducted a cost and life cycle assessment of high-volume cataract surgery. Her experience at Aravind led to a postdoctoral position at the University of Pittsburgh, where she conducted and compared environmental and cost assessments of cataract surgeries in the US and India, and recommended policy changes regarding material use in US ophthalmic surgery. She is also partnered with orthopedic surgeons at the University of Pittsburgh to run clinical trials of environmental interventions aimed at reducing waste in hand surgery.

Research topics

• Political Science
• Business
• Medicine
• Computer Science
• Artificial Intelligence
• Economics
• Economic growth
• Environmental planning
• Process management
• Medical emergency
• Environmental health
• Industrial organization
• Nursing
• Marketing
• Development economics
• Geography
• Environmental resource management
• Ecology

Selected publications

• Peer Review Report For: Understanding the Barriers to the Integration of Biodegradable Plastics into Healthcare Systems: A Scoping Review Protocol [version 1; peer review: 1 approved]

  2026-03-31

  peer-reviewOpen access1st authorCorresponding

  Introduction Given its substantially higher-than-average per capita plastic waste and the severe global environmental impacts associated with it, Ireland urgently needs alternatives and effective solutions within its heavily plastic-reliant health sector. Objective Within this protocol, a scoping review to identify key barriers to the widespread integration of biodegradable plastics into healthcare is outlined. Methods This will be achieved by mapping and synthesising existing literature and the current research landscape regarding the application of these biodegradable plastic materials. The principal objective of this review is to systematically identify barriers, such as the availability of waste disposal facilities, infection control considerations, sterilisation methods, cost, staff and management perspectives, knowledge levels and expertise, as well as other policy frameworks and regulations. This review will be guided by the Arksey and O’Malley methodological frameworks and also report recommendations of Peters et al. This review’s findings are expected to form a foundational knowledge base for health systems, researchers and policymakers. Conclusion The obtained evidence will inform the development of robust implementation and research strategies, which will be essential for incorporating biodegradable plastics into healthcare successfully. In turn, this will advance global targets for sustainability, including those relevant to a national context such as Ireland.

  PublisherDOI

• Extreme Urban Heat and Emergency Department Visits in Older Adults

  JAMA Network Open · 2026-03-20

  articleOpen access

  Importance: Health care systems can help protect patients from the increasing threat of extreme heat-driven morbidity and mortality. Electronic health records (EHRs) provide insight into trends and local variation in thresholds above which extreme heat is associated with emergency department (ED) use among at-risk patient populations. Objective: To examine associations between extreme heat exposure and all-cause ED visits among patients aged 65 years and older. Design, Setting, and Participants: This matched case-control study of patients seeking emergency care at an urban health care system during the summer (May 1 to September 30) from 2022 to 2024. Two New York City (NYC) EDs were included: (1) ED-1, predominantly serving Medicaid-enrolled patients from minoritized racial and ethnic groups, and (2) ED-2, predominantly serving White, privately insured patients. Included patients were aged 65 years or older and presented to ED-1 and ED-2 during the study period. Data were analyzed from April to August 2025. Exposures: Daily maximum heat index (HImax) values during the summer were calculated from the National Centers for Environmental Information monitor-derived recordings. Main Outcomes and Measures: Daily all-cause ED use counts were derived from EHRs, and extreme heat exposure-outcome curves were calculated. Daily HImax anomalies were calculated based on a 30-year baseline average. The cumulative odds ratio (OR) and 95% CIs were calculated. Results: This study included 55 200 ED encounters and represented 15 092 unique patients at ED-1 and 19 559 at ED-2 with a mean (SD) age of 74.9 (8.92) years at ED-1 and 74.9 (8.72) years at ED-2. Compared with ED-2, more ED-1 patients were female (8589 [56.9%] vs 10 767 [55.0%]), Hispanic (3544 [23.5%] vs 2576 [13.2%]), and Medicaid-enrolled (1321 [8.8%] vs 824 [4.2%]). At ED-1, daily HImax associations increased after 66 °F (OR, 1.10 [95% CI, 1.01-1.21]), peaking at 101 °F (OR, 1.24 [95% CI, 1.11-1.39]), and were higher on days with HImax anomalies between 15 °F (OR, 1.07 [95% CI, 1.01-1.13]) and 18 °F (OR, 1.10 [95% CI, 1.01-1.20]) warmer than average. At ED-2, daily HImax ED use associations were not significant and were significantly negative for days with HImax anomalies above 16 °F, nadiring at 21 °F (0.84, 95% CI [0.73, 0.95]) warmer than average. Conclusions and Relevance: In this case-control study of the association between heat exposure and ED use in adults aged 65 years and older, positive associations were only observed at ED-1, which served a predominantly lower-income population from minoritized racial and ethnic groups. These association thresholds were not fully captured by NYC heat advisories, which were triggered by 2 days above HImax 95 °F or any time above 100 °F, highlighting an opportunity for future research to develop targeted, risk-informed health care system-based heat warning strategies.

  PublisherOA PDFDOI

• Real and perceived barriers to effective use of cataract surgical supplies

  The Journal of Climate Change and Health · 2026-04-16

  articleOpen accessSenior authorCorresponding

  Introduction: Cataract surgery, among the most common procedures worldwide, significantly contributes to climate change through both solid waste and air pollution, highlighting the urgent need for targeted interventions. Implementation faces hurdles including legal constraints and concerns about infection risks and malpractice. Methods: This article examines federal and state regulatory structures around two key waste reduction strategies: reduction of multidose medications and distribution of partly-used operating room medication to patients post-surgery. Results: We find little-to-no legitimate regulatory barriers to either waste reduction practice. Dispensing and redistributing partly-used medication has been codified in law in some states. Evidence-based reports indicate minimal risks for infection with proper handling. From 1998 until August 2024, according to the Ophthalmic Mutual Insurance Company, there were no reported endophthalmitis lawsuits from using multidose eye drops perioperatively. Malpractice fears also appear to be generally unfounded considering guidelines by various professional organizations identifying these practices as acceptable standards of care and lack of related lawsuits. Conclusion: In order to implement evidence-based sustainability interventions, more education and training is needed to ensure clinicians and staff are aware of real and perceived barriers.

  PublisherDOI

• The climate and health impact of U.S. radiation therapy: estimating greenhouse gas emissions, DALYs, and potential of hypofractionation

  Radiotherapy and Oncology · 2025-09-22 · 2 citations

  article
  PublisherDOI

• CARBON FOOTPRINT OF ROUTINE ENDOSCOPIC PROCEDURES - A COMPREHENSIVE ASSESMENT IN THREE U.S. ENDOSCOPY UNITS

  Gastrointestinal Endoscopy · 2025-05-01

  article
  PublisherDOI

• Environmental and human health impact of contact precaution use for methicillin-resistant <i>Staphylococcus aureus</i> and vancomycin-resistant <i>Enterococcus</i> in Los Angeles County

  Infection Control and Hospital Epidemiology · 2025-11-07

  articleOpen access

  Abstract In LA County, contact precautions for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus require 7.3 million gowns annually generating 506 tons of plastic waste and 1.73 million kilograms of carbon dioxide equivalents, which cause the loss of 4.07 disability-adjusted life-years. Unintended consequences of gown use necessitates exploration of infection prevention alternatives.

  PublisherOA PDFDOI

• Harmonizing Diagnostic Ultrasound Practice with Environmental Sustainability: A Life Cycle Assessment of Diagnostic Ultrasound in a Single Adult University Hospital

  Journal of the American College of Radiology · 2025-10-05 · 2 citations

  articleOpen access

  OBJECTIVE: The purpose of this study was to assess the environmental impacts of ultrasound modality operations within the larger radiology department to find areas in which sustainability efforts may have the largest impact. METHODS: Life cycle assessment of the ultrasound section of a large academic hospital serving adult inpatient, outpatient, and emergency department patients was performed. In addition to assessing the energy use of ultrasound units themselves, this study included assessment of the carbon footprint and environmental impact of ultrasound unit production and disposal, ultrasound examination supplies like ultrasound gel and linens, and the data storage and imaging interpretation equipment. RESULTS: Unlike other imaging modalities, linens (35%; 5.5/17.0 metric tons CO2e) and disposable supplies (34%; 5.5 out of 17.0 t CO2e) accounted for the majority of greenhouse gas emissions, while production (7%; 1.1 out of 17.0 metric tons CO2e) and energy use (3%; 0.5 out of 17.0 metric tons CO2e) of the ultrasound machine were minor contributions to the carbon footprint of ultrasound. Gloves and ultrasound gel were the largest contributors to the carbon footprint among the single-use supplies. DISCUSSION: Ultrasound is a unique imaging modality in that the major environmental impacts come not from the modality use and production itself, but rather from the use of supplies needed to perform the examination. Giving the increasing use of ultrasound worldwide, focus on minimizing and optimizing the use of linens, gel, and other supplies can have a significant impact on the global carbon footprint of radiology departments. Strategies to reduce and optimize the use of supplies, in accordance with the principles of circularity, should be explored in future research.

  PublisherDOI

• Estimating the Climate Costs of Radiation Therapy in the United States: The Potential Role of Breast Hypofractionation in Reducing Greenhouse Gas Emissions

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

• Estimating the Carbon Emissions of a Single Prostate-specific Antigen Test: Results from a Cradle-to-grave Life Cycle Assessment

  European Urology Focus · 2025-08-05 · 3 citations

  article
  PublisherDOI

• A Comparative Environmental Impact Analysis of Screening Tests for Colorectal Cancer

  medRxiv · 2025-01-15 · 3 citations

  preprintOpen access

  BACKGROUND: Healthcare is a major contributor to global greenhouse gas emissions. Colorectal cancer (CRC) screening is one of the most widely used healthcare services in the US, indicated for approximately 134 million adults. Recommended screening options include fecal immunochemical tests (FITs) every year, CT colonographies (CTCs) every 5 years, or colonoscopies every 10 years. We compared the environmental impacts of these tests and identified opportunities for impact reduction. METHODS: We conducted a comparative life cycle assessment of three CRC screening strategies at the University of California, San Francisco. We performed on site audits to document the materials and energy used for each screening test. We used the ReCiPe 2016 method to estimate the environmental impacts of these procedures, measured by global warming potential (GWP) and damage to human health. We estimated the 10-year cumulative impacts of each screening strategy using a Markov reward model. We accounted for model uncertainty using hierarchical Monte Carlo simulations. FINDINGS: FIT-based screening had the lowest environmental impacts, with a roughly 20% margin of superiority over colonoscopies, and this finding was robust in sensitivity analyses. Across tests, the biggest cause of environmental harm was car-based transportation of patients and staff. Prioritizing FITs over screening colonoscopies in the US could enhance population health by roughly 5.2 million disability adjusted life years per decade. Transitioning to electric vehicles could reduce the GWP of all screening tests by 15-20%. INTERPRETATION: Given the similar efficacy and safety of these tests, payors should prioritize FITs for low-risk patients. Government initiatives to decarbonize transportation, incentivize telehealth, and mandate environmental product declarations will help reduce the environmental impacts of healthcare more generally. Our results call for a closer look at resource-intensive preventative health strategies, which could result in more harm than good if applied to a low-risk population. FUNDING: NIH, UCSF.

  PublisherOA PDFDOI

Recent grants

• Sustainable Healthcare Workshop

  NSF · $50k · 2018–2018

Frequent coauthors

• Alan L. Robin

  Johns Hopkins University

  33 shared

• Melissa M. Bilec

  University of Pittsburgh

  32 shared

• Rengaraj Venkatesh

  Aravind Eye Hospital

  30 shared

• Aravind Haripriya

  L V Prasad Eye Institute

  25 shared

• Pradeep Y. Ramulu

  25 shared

• Ashish M. Khodifad

  University of Michigan–Ann Arbor

  25 shared

• Suzanne W. van Landingham

  Visual Sciences (United States)

  25 shared

• Amy E. Landis

  17 shared

Education

• PhD, Civil and Environmental Engineering

  University of Pittsburgh

  2013

• BS, Civil Engineering

  Michigan Technological University

  2009

Awards & honors

• 2014-2015 Fulbright-Nehru Academic and Professional Excellen…