About Green Seal

The Green Seal Team

Green Seal’s staff works cohesively reviewing scientific research for standard development, implementing certification, fostering partnerships, and providing technical assistance to businesses and institutions.

Arthur B. Weissman, Ph.D.   President & CEO

Arthur B. Weissman, Ph.D., has led Green Seal as its President and CEO for two decades, and has over 35 years of experience in sustainability, environmental policy, standards, and enforcement. He served as founding Chair of the Global Ecolabeling Network from 1994-1997, and as international convener for ISO 14020 guidelines for environmental labeling. Prior to joining Green Seal, he was responsible for developing national policy and guidance for the Superfund program at the U.S. Environmental Protection Agency. Dr. Weissman also served in the U.S. Senate as a Congressional Science Fellow and worked for The Nature Conservancy managing preserve stewardship. His book, In the Light of Humane Nature: Human Values, Nature, the Green Economy, and Environmental Salvation, was published by Morgan James in 2014. He holds degrees from Johns Hopkins University, Yale University, and Harvard College. Email: kdanaher [at] greenseal.org

Mehreteab Masho  
Chief Financial Officer

Masho joined Green Seal in 1994. He is in charge of all financial and administrative aspects of the organization’s operations. He has over 30 years of experience in diversified accounting, budgeting, and financial forecasting. Prior to joining Green Seal, Masho held various accounting positions, including controller with Inter Systems Inc., a high-tech government contracting firm. Masho received his M.B.A. from the University of the District of Columbia. Email: mmasho [at] greenseal.org

Mark T. Petruzzi   Senior Vice President of Outreach & Strategic Relations

Mark leads Green Seal’s engagement with purchasers, industry groups, trade associations and other external organizations that share Green Seal’s goal of creating a more sustainable marketplace. Over the last 18 years, in his various roles in the Standards and Certification departments, Mark  has conducted research on the life cycle impacts of products and services, developed criteria to address key impacts, and evaluated products and services for compliance with Green Seal’s standards in a wide range of product and service categories. Previously Mark was Vice President of  Green Seal’s Certification Program. He holds a B.S. in mechanical engineering and a M.S. in civil and environmental engineering from The George Washington University.
Email: mpetruzzi [at] greenseal.org

Daniel Pedersen, Ph.D.  Vice President of Science and Standards


Daniel provides scientific and technological expertise and leads the creation and revision of Green Seal’s standards. He has over 20 years of experience in environmental science, research, fieldwork, chemical analysis, certification, laboratory accreditation and education. Prior to joining Green Seal in 2012, he worked as Director of Environment and Sustainability at a private Certification Body, with clients in the industrial, private, public and academic sectors. Previously he taught Atmospheric Chemistry at the college level, lectured widely on environmental issues, and directed air quality research at Hebrew University, Jerusalem. He is a certified lead auditor for ISO 9001, 14001 & 17025, studied in M.I.T’s Technology & Policy Program, and holds a Ph.D. in Environmental Engineering from M.I.T and a Bachelor of Science in Engineering from Swarthmore College. His personal interests include family, cycling, gourmet cooking, singing, and stage performance. Email: dpedersen [at] greenseal.org


Mark Stanland   Vice President of Client Services

Mark has over 25 years of experience in marketing and product development, and leads Green Seal’s new Client Services Program.  The Client Services Program is designed to provide tailored marketing support and strategic direction for manufacturers and service providers with, or working toward, Green Seal certifications.  Prior to joining Green Seal in January 2015, Mark led the development of Wausau Paper’s Green Seal program and green platform. He holds an M.B.A from Syracuse University and a bachelor’s degree from the University of North Carolina at Chapel Hill.
Email: mstanland [at] greenseal.org


Mary B. Swanson   Vice President of the Certification Program


Mary is director of certification and the technical lead for product certification. Prior to joining Green Seal, Mary worked as a research scientist with the University of Tennessee’s Center for Clean Products and Clean Technologies. Mary has 25 years of experience in environmental research and consulting, with a focus on evaluating the fate and effects of chemicals released to the environment, developing tools for evaluating cleaner products and cleaner technologies, and hazardous waste site remediation. She has a Master of Science degree in environmental engineering from the University of Minnesota and a Bachelor of Science degree in natural resources/water chemistry from the University of Wisconsin-Stevens Point. In her spare time, she enjoys gardening, artwork, and long walks in the woods. Email: mswanson [at] greenseal.org

Cerise Bridges  
Certification Specialist

Cerise joined Green Seal in 2009 as an intern with an interest in combining her education and work experiences in hospitality management and environmental policy. She became a staff member in 2010. She provides assistance and expertise to clients pursuing certification of Green Seal’s service-related standards. Originally from the Chicago area, Cerise has spent her adult life in Washington, D.C., where she earned a B.B.A. from Howard University and an M.A. in environmental policy from American University.
Email: cbridges [at] greenseal.org

Mac Clevenger   Outreach & Client Services Associate Coordinator

Mac graduated from the George Washington University with a degree in History. From an early age, he was instilled with a profound love of the outdoors, enjoying backpacking, fishing, skiing, and especially climbing the largest mountains in the US with his grandfather. It was this appreciation of the natural world and a desire to keep it pristine that spurred his passion for environmental sustainability. Mac began at Green Seal as an intern in the Science & Standards Department and was privileged to join the Green Seal family full-time in January 2015. Mac’s role at Green Seal has him supporting Green Seal’s clients in marketing their leadership, coordinating with potential partners, and speaking at conferences around the country on sustainability and Green Seal’s mission: to safeguard human and environment health and create a more sustainable economy. 
Email: pclevenger [at] greenseal.org

Holly Cypress
   Receptionist/ Administrative Assistant

Joining Green Seal in 2015, Holly has a B.S. in Business with a marketing major from the University of Maryland.  She has over 15 years of business and marketing experience in a variety of positions from account executive to corporate advertising manager. As a member of the Green Seal team, Holly looks forward to supporting our mission to help create a more sustainable environment. Email: hcypress [at] greenseal.org

Kat Danaher
   Executive Assistant to the President
                           Marketing & Communications Coordinator

Kat, a Virginia native, graduated from the University of North Carolina at Chapel Hill with a B.A. in communication studies and proficiency in French and Italian. Her professional experience includes over fourteen years of CEO-level executive support, as well as extensive event planning and logistics. She fosters dogs for DC-based City Dogs Rescue, and has enjoyed volunteering with other nonprofits, including anti-violence and HIV/AIDS groups. Kat joined Green Seal in 2011. Email: kdanaher [at] greenseal.org

Tracy Harvey
Environmental Scientist

Tracy has a Master of Science degree in Marine Science from the University of Texas at Austin, and a Bachelor of Science degree in Conservation and Environmental Sciences from the University of Wisconsin-Milwaukee. Over the past six years Tracy has worked as a research assistant, studying the fate and ecological impacts of various chemicals in aquatic environments, ranging from nanoparticles to large-scale oil spill disasters. Tracy joined the Green Seal team shortly after moving back to Madison in 2016. She is excited to be a part of an organization that is leading the way to a more sustainable world. Email: tharvey [at] greenseal.org

Nina Hwang
   Environmental Scientist 

Nina joined Green Seal in 2016 as an environmental scientist to work on product certification. Originally from California, she slowly moved east to earn a Bachelor of Science in Chemistry and Environmental Engineering from Rice University, followed by a Master of Public Health in Global Environmental Health from the George Washington University. Nina previously worked to protect the environment and public health at NRDC and the EPA. She spends her free time backpacking, baking, and exploring the nation’s capital. Email: nhwang [at] greenseal.org

Nathan Kloczko
   Environmental Scientist 

Nathan joined Green Seal in 2016 as part of the Certification team. Previously, he worked with the Southwest Pennsylvania Environmental Health Project to study how unconventional natural gas development impacts the health of communities and the environment. He graduated from Middlebury College with degrees in molecular biology and music, and earned a Master of Public Health from Yale University, concentrating in Environmental Health Sciences. Outside of Green Seal, Nathan enjoys singing in choirs, playing ultimate frisbee, and baking. Email: nkloczko [at] greenseal.org

Stacey Koch
  Senior Environmental Engineer

Stacey has been working with Green Seal since 2007, and her duties have included managing certification projects and developing standards. Prior to joining Green Seal, she was a lead environmental engineer with RMT, Inc. for 12 years, where she specialized in environmental design and management of projects, including industrial wastewater treatment, soil and groundwater remediation, surface water contaminant fate and transport, and sediment remediation. She holds a Master of Science in civil and environmental engineering from the University of Washington and a Bachelor of Science in civil and environmental engineering from the University of Wisconsin-Madison. She also maintains her Professional Engineer license in the State of Wisconsin. Her personal interests include reading, hiking, golfing, canoeing, and gardening. Email: skoch [at] greenseal.org

Terry Ross  
Special Projects/Quality Coordinator

Terry joined Green Seal in 2016 and is part of the Certification team. She has been involved in climate change and sustainability education for many years and most recently worked on the University of Wisconsin-Madison’s Massive Open Online Courses and Science Narratives projects. She created the Sustainable Business Certificate program at Madison College and is a former librarian. Terry also directs the Wisconsin state BiketotheLibrary.org program which combines two crowning human achievements: bikes and books! Email: tross [at] greenseal.org

Anne Shudy Palmer  
Environmental Scientist

Anne manages certification projects, as well as works with retail companies and hospitality businesses to help them become more sustainable. She joined Green Seal in 2009 and previously coordinated the Sustainability Leadership Graduate Program at Edgewood College, wrote sustainability case studies and reports for several Wisconsin organizations, and worked with Madison's utility company to create a locally focused carbon footprinting website. Anne has an M.S. in sustainability and a B.S. in math and film, both from the University of Wisconsin-Madison, and is a LEED Accredited Professional. She enjoys reading, writing, playing soccer, and generally getting outside. Email: aspalmer [at] greenseal.org

Callie Taylor   Certification Coordinator

Callie joined the Green Seal team in 2013.  Callie coordinates the certification evaluation and monitoring process and works with clients to ensure continued compliance with the Green Seal standards. Prior to working with Green Seal, Callie was the Program Coordinator with ToxServices, where her primary responsibility was to manage client evaluations for DfE (now Safer Choice) recognition and CleanGredients. She graduated with a B.S. in Marine Biology and Environmental Science from the University of North Carolina Wilmington. She enjoys reading, being outside, southern food, long walks on the beach, and hanging out with her family.  Email: ctaylor [at] greenseal.org

Brielle H. Welzer   Environmental Scientist

Brie joined Green Seal in 2012. She supports the development of new standards, manages the revisions of issued standards, conducts sustainability analyses, and leads science communications initiatives. Prior to joining Green Seal, Brie provided mission and research support to the U.S. Environmental Protection Agency (EPA), and managed innovative programs in partnership with the American Association for the Advancement of Science (AAAS). She graduated with a B.S. in Environmental Science and Geochemistry from the University of Rochester, and has an M.B.A. in Sustainable Business. Email: bwelzer [at] greenseal.org

Some photography contributed by Laura Burt, www.burtla.smugmug.com