Our Team
Melissa A. McDiarmid, MD, MPH, DABT
Dr. McDiarmid is Professor of Medicine, Epidemiology and Public Health and Director of the University of Maryland School of Medicine’s Division of Occupational and Environmental Medicine where she teaches, sees patients, and directs a surveillance program for Veterans exposed to toxic environmental agents.
She received her B.A. degree from the University of Maryland Baltimore County, in Biological Sciences; her M.D. from the University of Maryland at Baltimore and her M.P.H. from The Johns Hopkins School of Public Health where she also completed fellowship training in Occupational Medicine. She is board-certified in Internal Medicine, Occupational Medicine and Toxicology.
Dr. McDiarmid was Director of the Office of Occupational Medicine for the U.S. Occupational Safety & Health Administration (OSHA) in Washington, D.C., a position she held for five years. Prior to this, she was Assistant Professor of Environmental Health Sciences at The Johns Hopkins School of Hygiene and Public Health where she directed the Occupational Medicine residency. She retains her Hopkins affiliation as an adjunct professor of Environmental Health Science.
Dr. McDiarmid currently co-directs the University of Maryland, Baltimore, WHO Collaborating Center for Occupational Health with principal responsibilities to provide technical expertise to low and middle- income countries requesting assistance strengthening health workforce protections.
She has authored numerous journal articles and book chapters on occupational and environmental medicine topics related to medical surveillance and management, reproductive hazards, occupational cancers, military environmental exposures and healthcare worker protections in both low-income and well-resourced settings.
Dr. McDiarmid's Faculty Profile
Marianne Cloeren, MD, MPH
Dr. Cloeren is board-certified in both Occupational Medicine and Internal Medicine. After graduating from the University of Pennsylvania with a B.A., she attended Temple University School of Medicine, graduating with her M.D. in 1987, and then entered post-graduate training in Internal Medicine, followed by Occupational Medicine, in the Johns Hopkins system, where she earned a Master of Public Health in 1991. She has broad clinical experience, including primary care of Veterans, hospital medical service management, consulting, military occupational medicine and case management.
Dr. Cloeren has a long-standing interest in medical education, in particular online training of clinicians, and in 2017 completed coursework at the University of Wisconsin - Stout, earning a Graduate Professional Development Certificate in Instructional Design. She has applied this training to develop several engaging interactive online medical education courses.
Dr. Cloeren has particular interest and expertise in teaching medical providers how to make decisions that do not inadvertently lead to prolonged work disability in their patients. She is also an experienced educator on the topic of opioid decision-making, including clinical appropriateness, alternatives, informed decision making and monitoring. She developed and leads an innovative 100-hour elective for pre-clinical medical students and is faculty for two climate change focused electives, including one that is interprofessional.
Dr. Cloeren has been working since 2019 on projects seeking the partnership of employers in supporting employees and their families struggling with opioid use disorder, and in 2024 established a workplace-facing Overdose Response Program. This program delivers naloxone training and distributes naloxone to workers in industries exhibiting the highest risk for opioid overdose, including construction.
Dr. Cloeren is the Medical Director of the Building Trades National Medical Screening Program (BTMed), which provides screening exams for construction workers employed at Department of Energy nuclear weapons facilities, and conducts research on the health impact of this work.
Dr. Cloeren is a leader in the American College of Occupational and Environmental Medicine, having served two terms on the Board of Directors, serving as past Chair of the Council on Occupational and Environmental Medicine Practice, past Chair of the special interest section on Work Fitness and Disability, and serving as a member of the Council on Education and Academic Affairs.
Dr. Cloeren joined the faculty in April 2017, supports the Division’s Depleted Uranium Program, providing clinical surveillance related to potential adverse impacts of depleted uranium exposures in Veterans.
In her clinical practice, Dr. Cloeren assists patients dealing with work disability issues, workers’ compensation challenges, fitness for work questions and other complicated situations involving a wide range of health problems and work or work exposures.
Joanna Gaitens, MSN, MPH, PhD
Dr. Gaitens is an Associate Professor within the Division of Occupational and Environmental Medicine at the University of Maryland School of Medicine. Her areas of expertise and interest include clinical surveillance of metal-exposed populations, the use of urine biomonitoring to assess exposure, development and utility of public health registries, and protection of health workers. She currently directs the VA’s Toxic Embedded Fragment Surveillance Center and Registry and is a key member of the Depleted Follow-up Program. She also co-directs the division’s activities as a WHO Collaborating Center for Occupational, providing support and expertise for health worker protections in the Americas and African regions.
Dr. Gaitens received her A.D.N. Degree from Norwich University in 1994; her BSN Degree from the University of New Hampshire in 1997; her MSN/MPH Degree from the Johns Hopkins School of Nursing and Bloomberg School of Public Health in 2000; and her PhD from the Johns Hopkins Bloomberg School of Public Health in 2006. Prior to joining the University of Maryland faculty in 2008, Dr. Gaitens worked for several years as a nurse in skilled care before transitioning into public health. Her dissertation focused on the neurobehavioral effects associated with polychlorinated biphenyl exposure in older adults. She also has worked in the field of lead poisoning prevention.
Sammy Almashat, MD, MPH
Dr. Almashat graduated from West Virginia University with a BA/BS in Biology/Psychology, and a Minor in Spanish; an MD from West Virginia University; and an MPH from the Johns Hopkins School of Public Health where he also completed a residency in General Preventive Medicine and Public Health. He completed a second residency in Occupational and Environmental Medicine at the University of California-San Francisco.
He previously worked at Public Citizen’s Health Research Group, conducting research-based advocacy in the areas of pharmaceutical and medical device safety and policy; universal healthcare access; corporate health fraud; and occupational health and safety. After completing an Occupational Medicine residency, he worked for several years at a high-volume occupational medicine clinic, treating a wide spectrum of acute and chronic workplace injuries and illnesses; conducting employee health and Department of Transportation medical exams; and completing permanent impairment evaluations.
At UMB, Dr. Almashat’s primary focus areas have involved longitudinal surveillance, and research, of cohorts of veterans exposed to depleted uranium and with potential systemic metal exposures from embedded munition fragments; and of former construction workers as part of a U.S. Department of Energy-funded program (Building Trades National Medical Screening Program, or BTMed), while continuing his prior research into the health consequences of armed conflicts, including the ubiquitous problem of toxic chemical exposures among civilians.
He helps direct health-related administrative and clinical services for the University of Maryland’s Faculty Physicians (FPI) outpatient clinic employees and oversees pre-employment and periodic medical surveillance of University of Maryland-Baltimore (UMB) employees with hazardous exposures, such as those arising from work with lab animals (principally allergies), chemical toxins, and infectious pathogens. He is also a consultant to Occupational Health providers at University of Maryland-College Park.
Dr. Almashat is board-certified in Occupational Medicine and General Preventive Medicine & Public Health.
Dr. Almashat's Faculty Profile
Patricia Welsh Gucer, PhD
Dr. Gucer is an Assistant Professor at the University of Maryland School of Medicine. She is co-Principal Investigator on two studies examining safe resident lifting practices and their impact on caregiver injuries in long-term care facilities. She also works on a surveillance study of Gulf War Veterans exposed to depleted uranium.
Dr. Gucer received her A.B. Degree from Dumbarton College of Holy Cross in 1963, and her PhD from the Johns Hopkins University Department of Sociology in 2001.
Dr. Gucer has taught secondary school science, managed data for a longitudinal study of school children, and has been Baltimore Study Manager for a large multi-center clinical trial testing the effects of beta carotene on the incidence of lung cancer.
Sheila Williams, BS, MS
Ms. Williams is our executive administrative assistant and focal point of the division. Before joining our program in 2000, she worked in health care for 10 years. Her wide variety of skills comes from working in such various environments as mental health, family preservation, and shelters for women, and administration. She provides executive assistance to the division faculty and staff while also serving our programs’ patients, clients and students.
Ms. Williams received her Executive Administrative Assistant A.A. Degree from Baltimore City Community College. She is currently pursuing her BS Degree in Human Resources Management from the University of Maryland University College.
Tracy S. Roth, RN, BSN
Tracy Roth is the Nurse Manager for FPI Employee Health. She also serves as a research nurse on the Occupational Health team. She organizes outreach programs, health education and the development of educational materials. She has also served as the study coordinator for several University of Maryland medical surveillance programs.
Tracy Roth received her Bachelor of Nursing Science degree in 1980 from the University of Bridgeport, Connecticut and her Master’s Degree in Community/Public Health Nursing from the University of Maryland, Baltimore in 2018. She has worked in multiple clinical, public health and research settings throughout her career.
Marian Condon, MS, RN
Marian Condon has a BSN from Johns Hopkins School of Nursing and an MS in Community/Public Health Nursing from the University of Maryland, School of Nursing. She has worked in the areas of environmental and occupational health and has given presentations and written articles on a variety of environmental and occupational health topics. She works as a VA employee on the Toxic Embedded Fragment Surveillance Center as well as the Depleted Uranium program with the Division of Occupational and Environmental Health at the University of Maryland, School of Medicine.
Marc Oliver, RN, MPH, MBA
Mr. Oliver is a research nurse and data analyst for the VA’s Depleted Uranium program and various research projects, including collaborative work with NIOSH. Mr. Oliver does data management for the Employee Health program for the faculty practice of the University of Maryland School of Medicine.
Mr. Oliver received his A.D.N. Degree from Alfred State College in 1996; his MPH Degree from the Johns Hopkins Bloomberg School of Public Health in 1998 and his MBA from University of Maryland University College in 2005.
Tsion Girmay, MPH, BSBS
Tsion Girmay is the Lead Research Analyst for the Division of Occupation and Environmental Medicine. With her expertise in database management and research coordination, she oversees the development and establishment of best practices and protocols for data collection, quality, warehousing, analysis, and reporting to support various clinical surveillance and research initiatives, including the Depleted Uranium and Toxic Embedded Fragment Surveillance Center Programs. Her work also includes managing institutional review board (IRB) processes.
Tsion has a Master of Public Health in Epidemiology from Louisiana State University Health Sciences Center, a Bachelor of Science in Biological Sciences from Southeastern Louisiana University and is pursuing a PhD in Epidemiology at the University of Maryland Baltimore.
Walter Frauman, PhD
Dr. Frauman is an Exposure Assessment Specialist working on the VA’s Military Exposures Research Project (MERP), handling projects advancing research into the effects of exposures to toxicants incurred during military service.
He received his B.A. from St. Mary’s College of Maryland in Chemistry in 2013 and his PhD in Chemistry and Biochemistry from the University of California San Diego in 2022.
Amber Quinlan, BA
Amber is a Senior Research Project Coordinator, working with Dr. Cloeren on several projects related to opioid use, overdose, and recovery.
She received her Bachelor of Science Psychology at Bucknell University and is pursuing a Master of Professional Studies (MPS) in Clinical Psychological Science at the University of Maryland.
Joshua Burdick, ABA
Joshua Burdick is an Administrative Assistant for the Division of Occupational and Environmental Medicine and FPI Employee Health.
Joshua has an Associate of Business Administration from Berkshire Community College.
Adjunct Faculty
Victoria Cassano, MD, MPHIL, MPH, FACPM, FACOEM
Jose Centeno, M.Sc., PhD., FRSC
Barbara Anne Curbow, PhD, MA, BA
Steven Deck, DM, MBA
Carrie Dorsey, M.D.
Richard Duffy, MS
Lori Edwards, DrPh, MPH, RN, PHCNS-NC
Melissa Frisch, M.D., M.P.H.
Stella Hines, MD, MSPH, FACOEM
Christopher Jankosky, MD, MPH
John Kalinich, Ph.D.
Boris Lushniak MD, MPH
Kathleen McPhaul, RN, MPH, PhD
Donald Milton, M.D., Dr. P.H.
Amber Mitchell, DrPH, MPH, CHP
Gary Orr, PE, M.S.
Claudio Muller-Ramirez, PhD, MSc, PharmD
Jeffrey Stull, B.S., M.S.