Leadership Team

Thomas H. Winters, MD, FACOEM

OEHN Chief Medical Officer and Principal Partner

Board Certified in Occupational Medicine
Board Eligible in Infectious Diseases
Board Certified in Internal Medicine
Certified Medical Review Officer
Certified Independent Medical Examiner.

Thomas H. Winters MD, FACOEM, FACPM, is the Medical Chief of the Occupational & Environmental Health Network (OEHN) and the New England Baptist Hospital Occupational Medicine Center. He is currently a visiting lecturer at Harvard Medical School. Dr. Winters has over 25 years experience in occupational and environmental medicine. His previous positions have included:

  • Medical Director of a national occupational medicine provider
  • Medical Director for several manufacturing companies
  • State Police Surgeon – Massachusetts State Police, and
  • Owner/Medical Director of Medsite – an occupational and primary care medicine center.

Dr. Winters is board certified in Occupational Medicine and certified as a Medical Review Officer in accordance with federal standards (DOT) for drug testing. Dr. Winters has expertise in musculo-skeletal disease, toxic tort and radiation exposures, occupational and infectious diseases, and corporate medical consulting. Dr. Winters frequently serves as a visiting lecturer at Harvard Medical School and Harvard School of Public Health and provides medical director oversight for Harvard University’s BSL 2/3 labs.

The Occupational & Environmental Medicine Residency Program at the Harvard School of Public Health (HSPH) awarded Dr. Thomas H. Winters the “Clinical Professor of the Year Award” for 2007-2008. The award recognizes dedication, leadership and invaluable contributions to the advancement of the residency program. Dr. Winters was honored at an awards dinner on May 9th, 2008.

Lee Okurowski, MD, MPH, MBA

Chief Executive Officer, Chief Financial Officer,
Principal and Medical Director


Dr. Okurowski holds a Medical License in both Massachusetts and Rhode Island. He is Board Certified in Occupational Health and Board Eligible in Preventive Medicine.

Dr. Okurowski is currently Medical Director at the following hospitals: Caritas Carney Hospital, Caritas Good Samaritan Hospital, Holy Family Hospital, St Anne’s Hospital and U Mass Memorial Medical Center. He also serves as medical and clinical director of Landmark Occupational Health in Rhode Island and Chief Medical Consultant for H.C. Starck/Bayer Company.

Dr. Okurowski graduated from Dartmouth Medical School and went on to earn a Master of Public Health, Health Policy & Management/Occupational Medicine from the Harvard School of Public Health. Dr. Okurowski also has a Master of Business Administration from The Wharton School.

Dr. Okurowski is a member of numerous professional medical organizations, including the American College of Occupational and Environmental Medicine, the New England College of Occupational and Environmental Medicine, the American Medical Association, and the American College of Physician Executives.

Karin Sullivan

Executive Director

Karin Sullivan joined Occupational and Environmental Health Network’s (OEHN) leadership team in July 2013 as Executive Director.

Karin’s background includes several years managing occupational medicine centers and programs, including a position as former Director of Training and Special Projects for the Care Group Occupational Health Network. Here she contributed to the strategic planning, infrastructure development and operational initiatives of the network and also chaired the Annual Lewis H. Millender M.D. Occupational Medicine Conference for four years. Most recently Karin managed a primary care medical group practice where she was accustomed to managing change on a daily basis in a dynamic health care environment.

Karin’s role is to provide administrative leadership and support of the daily business functions including operations, human resources, financial, business development, communications and strategic planning.

Karin has an M.Ed. in Instructional Design from the University of Massachusetts – Boston and a B.S. in Healthcare Administration from Stonehill College.

Dieter Affeln, MD

Occupational Health Medical Director

Board certified in Occupational Medicine and a certified MRO (Medical Review Officer), Dr. Affeln brings extensive occupational health experience to OEHN.

Dr. Affeln received his medical diploma and license to practice medicine from the University of Cologne in Germany. He then went on to receive his Masters in Public Health with a specialty in Occupational and Environmental Health from Harvard School of Public Health. He has been a member of the Occupational Medicine Board.

After completing his training in general practice at a family practice in an urban London neighborhood, Dr. Affeln became a fellow in Palliative care at the Cleveland Clinic Foundation.

Dr. Affeln currently provides Medical Director Leadship for OEHN at Nashoba Valley Medical Center in Ayer, MA. As the current Medical Director in the Employee Health Department at Beth Israel Deaconess Medical Center, Dr. Affeln consults on treatment of workplace injuries and illnesses. He also evaluates employee fitness for duty, disabilities, in addition to overseeing surveillance and health and safety concerns. Dr. Affeln is on the faculty of Harvard Medical School. He was previously the Medical Director of the Chelsea Occupational Health Services.

David Rosmarin, M.D.

Chief of Psychiatric Services

Dr. Rosmarin has 28 years experience in criminal, civil, and occupational matters in Forensic Psychiatry. Dr. Rosmarin evaluates employees for fitness for duty, disability claims, workplace harassment, and personality assessments. He also supplies complex disability evaluations, including those for employees with contested disability claims involving both a physical and a psychiatric basis. As a consultant to senior management, Dr. Rosmarin provides threat assessments, personality evaluations of new hires, discreet psychiatric services, and security assessments, as well as consulting about difficult employees. He also provides risk management consultation, including critical incident debriefing and litigation support services.

Dr. Rosmarin is a graduate of Boston University School of Medicine and served his internship at Boston City Hospital. He went on to a residency at the University of Massachusetts Medical Center where he was Chief Resident in Forensic Psychiatry. He was also a Special Student at Harvard Law School.

Dr. Rosmarin currently has a clinical appointment at Harvard Medical School. He is Board Certified in both Psychiatry and Forensic Psychiatry. Dr. Rosmarin provides consultation services for a number of private companies and law enforcement departments. He is on the Executive Council of the American Academy of Psychiatry and the Law and Chairs the Committee on Peer Review of Psychiatric Testimony. He has also received the American Psychiatric Association Distinguished Life Fellow Award.

 Robert Mullaly, Ph.D., ABPP (Clinical)

 Licensed Psychologist
 Psychological Services





Dr. Mullaly is a Board Certified, Licensed Psychologist with extensive experience working with police, fire and law enforcement. He has over twenty-five years of broad-based professional experience in such areas as disability, school and court ordered evaluations, testing, clinical consultations, employee assistance program consulting and out-patient private practice. He received his undergraduate degree in Psychology from Northeastern University in 1968 and his Ph.D. in Clinical Psychology from University of Tennessee in 1975. Along with his work at OEHN, he currently operates a private practice in Marblehead, Massachusetts.

See Mullaly Associates website for more information about Dr. Mullaly.

 Michael Amster, CIH, CSP, PE, CHMM, TURP

 Environment, Health and Safety Specialist




Michael Amster has more than 30 years experience as a manager and individual contributor in insurance loss control, consulting, and industry at both corporate staff and plant levels. Mr. Amster’s experience has spanned sales and marketing of EH&S consulting services, information systems, computer and web-based interactive training applications. He has been a major contributor in strategic, tactical, and operational roles. This experience has included supporting the needs of companies with less than 100 employees to members of the Fortune 500. He has managed award winning programs that have achieved demonstrated significant injury and cost reductions. Find out more about Mr. Amster at www.MBAmster.com

 Terry B. Snyder, BSBME, MBA

 Senior Ergonomics Consultant






Terry Snyder has over 20 years experience as an Ergonomics Specialist encouraging companies to takes a participatory and interdisciplinary approach to developing innovative ergonomic solutions that decrease risk while improving productivity, quality, and costs.

She has provided consultations that have addressed ergonomics in a wide variety of workplace environments including office, laboratory, university, and manufacturing settings. Ms. Snyder has also provided ergonomic consulting for process improvement teams, including lean manufacturing and Kaizen programs.

Ms. Snyder received engineering degrees in electrical and biomedical engineering from Case Western Reserve University. During eleven years at Hewlett Packard, Ms. Snyder worked in R&D, marketing, and manufacturing where she focused on human factors engineering. In 1988, Ms. Snyder completed an MBA at Simmons Graduate School of Management, and started the consulting firm of P.S. Associates. In 2006, P.S. Associates, LLC became a network provider for the Occupational and Environment Health Network (OEHN).

Ms. Snyder’s publications have focused on organizational issues related to successful implementation of ergonomic interventions. They include Business Analysis in Occupational Health and Safety Consultation, Journal of Occupational Medicine Oct 1991; The Organizational Response – Influence on CTDs in the Workplace – published in Beyond Biomechanics by Steve Sauter in 1996, and Under-Reporting of Work-Related Upper Extremity Disorders, Ergonomics, 1999.

Learn more about Ms. Snyder and PSAssociates at http://www.psaergoconsult.com/




Milda Walkley, RN, BA, COHN-S, CCM, CDMS

Ms. Walkley is an Occupational Health Specialist. She brings OEHN significant experience in occupational health, disability and workers’ compensation case management. OEHN and our clients will benefit from her knowledge in the following areas:

  • Clinic Operations & Productivity
  • Electronic Medical Record System
  • Workers’ Compensation
  • Medical Case / Risk Management
  • Travel Health
  • Medical Surveillance
  • Policies & Procedure Development

Ms. Walkley has a Bachelor of Arts in Psychology from Emmanuel College; she was a Clinical Fellow in Early Intervention; has a Diploma in Nursing and maintains COHN-S and CCM certifications. She is a licensed Registered Nurse in both Massachusetts and New Jersey. Ms. Walkley is currently based at Tufts University where she provides Occupational Health services for employees working in bioresearch. She also assists OEHN with projects for other hospitals and bioresearch organizations. Other responsibilities include implementation of an electronic medical record system.

Lori Winters, On-Site Manager

Donna Baker, Operations Manager

Shelly Herbst, Disability Coordinator