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 has over 30 years of experience in environmental programs, policy, standards, and enforcement. He has spent over half that time at Green Seal, which he has led for the past fifteen years. In his sustainability work, he has also served as founding chair of the Global Ecolabeling Network and as international convener for ISO standards. 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. He also served as a Congressional Science Fellow and worked for The Nature Conservancy in Connecticut. He holds a Ph.D. from Johns Hopkins University in physical geography and environmental science, a master’s degree in natural resource management from Yale School of Forestry and Environmental Studies, and a bachelor’s degree from Harvard College. His outside interests include family, music, hiking/walking, birding, reading, writing, and thinking. Arthur has recently written In the Light of Humane Nature, a book on human values, nature, the green economy, and environmental salvation. Visit Arthur's website to learn more. 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

Linda H. Chipperfield
   Vice President of Marketing & Communications

Linda has over 25 years of experience in creative marketing and guides the brand communication efforts for Green Seal. Prior to joining Green Seal in 2006, she served as Creative Director and Team Leader at Noble Communications, and owned and operated a design and marketing shop in Springfield, Missouri. She earned a B.F.A. in design from Southwest Missouri University and has extensive experience in media communications. Linda serves on the board of directors for the Global Ecolabelling Network and conducts peer reviews of the network members. Linda also served on the executive committee and conservation committee for the Missouri Sierra Club and as a delegate for the regional conservation committee for the National Sierra Club. Email: lchipperfield [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

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

 Liliana Cami
   Accounting Associate

Liliana joined Green Seal in 2009 as Accounting Associate responsible for accounts payable, accounts receivable, payroll and other related duties. She came to the United States from Albania in 1991 and has a degree from Albania University with a concentration in Business Administration. Prior to joining Green Seal, she worked for 16 years in an administrative/ accounting role in the private sector. Liliana is enthusiastic about working together to reach Green Seal’s goal of a better, more sustainable world. Email: lcami [at] greenseal.org

Mac Clevenger   Marketing & Outreach Associate

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 interest in environmental sustainability. Mac began as an intern in the Science & Standards Department and was privileged to join the Green Seal family as a full-time employee in January 2015. It is his fervent desire to uphold Green Seal’s mission, protecting the environment and creating a more sustainable economy.
Email: pclevenger [at] greenseal.org

Kathryn Danaher
   Executive Assistant to the CEO

Kat, a Virginia native, graduated from the University of North Carolina at Chapel Hill with a B.A. in communication studies. Her professional experience includes over nine years of CEO-level executive support, as well as extensive event planning and logistics. She has enjoyed volunteering with several community-based nonprofits, including animal rescue groups and HIV/AIDS causes. Email: kdanaher [at] greenseal.org

Lisa Nash   Marketing & Communications Associate

Lisa joined the Green Seal team in 2014 after interning with the Marketing and Communications department. Lisa Nash graduated from Tulane University with degrees in International Relations and Asian Studies. While living abroad in Beijing and experiencing a culture of poor environmental policies, Lisa committed herself to a career in sustainability. Lisa developed skills in social entrepreneurship and innovative waste management solutions through her work with the Green Project of New Orleans. She also developed skills in communications while interning with a business magazine in Beijing, Agenda, and a grassroots environmental campaign organization in Maryland, The Chesapeake Climate Action Network. Email: lnash [at] greenseal.org

Susan Heaton
   Director of National Accounts Development

Susan has over 15 years of experience in sales and marketing. Prior to joining Green Seal in 2010, she worked as a raw material manager for Procter & Gamble. During her 15 years there, she was a member of many new product launch teams. As a member of the Outreach and Strategic Relations team, Susan is responsible for new business development and client relations. Susan holds a B.S. in business administration from North Carolina Wesleyan College. Email: sheaton [at] greenseal.org

Cassie Johnson
  Environmental Engineer II

Cassie began working with Green Seal in 2009 as an environmental engineer and focuses her time on performing product reviews in the Certification Program. Prior to joining Green Seal, she was an environmental engineer with RMT, Inc. for 10 years, where she specialized in project management, technical coordination, environmental compliance, and environmental design, including defining and remediating soil, groundwater, and sediment contamination. She also worked in state government for five years, focusing on air, wastewater, and health regulation compliance. She holds a B.S. in civil and environmental engineering from the University of Wisconsin-Madison. Her personal interests include gardening, hiking, and traveling. Email: cjohnson [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

Anne Shudy Palmer  
Environmental Scientist

Anne joined Green Seal in 2009. She manages certification projects and works with raw material suppliers on chemical composition disclosures. Before Green Seal, she 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. She enjoys reading, writing, playing soccer, and generally getting outside. Email: aspalmer [at] greenseal.org

Anne Hancock
  Program Development Specialist

Anne joined the Green Seal Certification team in 2010. She coordinates the certification evaluation and monitoring process and works with clients to ensure continued compliance with the Green Seal standards. Before coming to Green Seal, she worked at The Center for a New American Dream as the responsible purchasing network membership coordinator. Anne graduated with a B.A. in economics and environmental studies from The College of William and Mary. Email: ahancock [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


Brielle H. Welzer   Environmental Scientist

Brie joined Green Seal in 2012. She assists in the development and revision of Green Seal's standards, conducts sustainability and market research, and helps to maintain a technical library. In 2015, Brie shifted from her Green Seal role in communications to support the Science and Standards Department. Prior to joining Green Seal, Brie provided mission support to the U.S. Environmental Protection Agency (EPA), and coordinated innovative science communication 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

Greg Graf   Environmental Scientist

Greg joined Green Seal in 2014 and performs product certification reviews. He brings over 25 years of experience as an analytical chemist working in environmental laboratories and performing environmental data review for environmental consultants. Greg also has several years of experience in quality management in both the laboratory and pharmaceutical industries. Greg holds a B.S. degree in chemistry from the University of Wisconsin. In his spare time he enjoys woodworking, biking and flying R/C airplanes. Email: ggraf [at] greenseal.org 

Chelsea Chandler   Environmental Scientist

Chelsea joined Green Seal in 2014, where she manages product reviews in the Certification Program. Prior to Green Seal, she worked in the Stockholm Environment Institute’s Climate and Energy group where she developed tools to quantify anticipated emissions reductions from mitigation strategies and policies, conducted long-term scenario modeling, and analyzed carbon offset methodologies. Chelsea has a M.E.M. in global change science and policy from the Yale School of Forestry & Environmental Studies, and a B.A. in Atmospheric Science from the University of California, Berkeley. In her free time, she enjoys biking, soccer, snowboarding, and traveling. Email: cchandler [at] greenseal.org

Callie Taylor   Certification Coordinator

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 recognition and CleanGredients. She graduated with a B.S. in Marine Biology and Environmental Science from the University of North Carolina Wilmington.  Email: ctaylor [at] greenseal.org

Ben Walsh
Project Coordinator

Ben joined Green Seal in 2013 and works with the Science and Standards, Institutional Greening, and Outreach and Strategic Relations Departments. He earned his BA at UNC Asheville in Political Science and Mass Communications.  He graduated with an MA in Political Management and an MA in Environmental Resource Policy from George Washington University. While at GW, he served as part of the Office of Sustainability’s Green Office Network. His personal interests include photography, traveling to National Parks, and baseball. Email: bwalsh [at] greenseal.org

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