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About Us

Who We Are

At Greenleaf Labs, we strive to re-define the relationship between growers, laboratories, and consumers of medical marijuana. By investing in industry-leading technologies and experienced personnel, our laboratory delivers rapid, accurate, and consistent results with complete transparency. Our combination of customer service and scientific innovation simultaneously promotes consumer safety and client growth. Through customizable and flexible support, our partnership is geared towards your success.

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Meet Our Team

Roulette Massey
Laboratory Director
Roulette Massey

Roulette Massey serves as Laboratory Director at Greenleaf Labs and brings over 20 years of laboratory experience, including hospital laboratory management. She holds two bachelor’s degrees in Health Sciences and Medical Technology, along with a Chemistry minor.

Roulette provides leadership in laboratory operations, quality oversight, and regulatory compliance. Naturally introverted and highly self-motivated, she thrives on setting goals and continually pushing herself to achieve them. Outside of work, she enjoys watching competitive sports and spending time outdoors with her dachshunds.

Brennan Dooly
Operations Manager
Brennan Dooly

Brennan Dooly serves as Operations Manager at Greenleaf Labs, bringing a strong background in healthcare operations, clinical laboratory management, and the cannabis industry. Prior to joining Greenleaf Labs, Brennan oversaw operations for a clinical laboratory and medical clinic, where he developed a reputation for efficiency, regulatory compliance, and effective team leadership.

Brennan holds a bachelor’s degree in business management from the University of Arkansas–Fort Smith, where he also competed as a collegiate baseball player. Balancing academics and athletics fostered discipline, adaptability, and the ability to thrive in fast-paced environments—skills that translate directly to the evolving cannabis testing landscape.

Today, Brennan focuses on delivering consistent, compliant, and customer-centered services that meet industry standards while supporting Oklahoma’s cannabis communities.

Crystal Harger
Office Manager
Crystal Harger

Crystal Harger has been with Greenleaf Labs since its founding in 2021 and has played a key role in building laboratory operations from the ground up. As Office Manager, she keeps the office running smoothly by managing logistics, coordinating schedules, handling documentation, and ensuring every sample is properly labeled, tracked, and handled with precision.

Crystal thrives on organization, problem-solving, and maintaining operational flow—especially when unexpected challenges arise. Her behind-the-scenes work allows the scientific team to remain focused on testing and quality.

Hannah McGowin
QA / Technical Manager
Hannah McGowin

Hannah McGowin serves as QA/Technical Manager at Greenleaf Labs and is a Medical Laboratory Scientist with over a decade of experience spanning clinical and cannabis laboratories. She spent nine years in healthcare supporting patient care through high-complexity diagnostic testing before transitioning into the medical marijuana industry.

Hannah brings a healthcare-driven commitment to quality systems, method development, and regulatory compliance, helping bridge traditional clinical laboratory standards with the evolving cannabis testing sector. Her expertise includes analytical instrumentation, data review, quality management systems, and cross-functional collaboration to support accurate, science-driven results.

Outside of work, Hannah is married, the mother of a five-year-old son, and enjoys reading, shopping, and gardening.

Abbey Jarrard
Assistant Laboratory Director
Abbey Jarrard

Abbey Jarrard is a Medical Laboratory Scientist with over 10 years of laboratory experience and plays a key role in daily laboratory operations at Greenleaf Labs. Since entering the cannabis testing industry in 2022, she has been deeply involved in analytical testing, quality assurance, and regulatory compliance.

Abbey is known for her attention to detail, reliability, and commitment to producing accurate, defensible results. She takes pride in supporting laboratory excellence and continuous improvement. Outside of the lab, Abbey enjoys spending time with her husband and four-year-old son, reading, building LEGO projects, and cheering on the Arkansas Razorbacks.

Joseph Reynolds
Laboratory Analyst
Joseph Reynolds

Joe was born and raised on a small farm in Camden, AR. He attended Arkansas Tech University in Russellville, AR, where he met his wife; and graduated in 2002 with a Bachelor of Science in Agriculture Business. He moved to Fort Smith, AR in 2003 and began his adventure in field of laboratory Sciences. He worked for OK Foods for 7 years with an emphasis in Serology and Microbiology, next he spent a brief period at Pfizer specializing in virology and sanitation, he then spent the next 10 years at Tyson foods furthering his knowledge in Microbiology and even becoming a manager in the lab for 3 years while also becoming a novice in certain chemical analysis before leaving Tyson to work closer to home and raise a child. Joe entered the cannabis field in August of 2020 as a Microbiology analyst. He continued to hone his skill as a Microbiologist and started expanding his knowledge in Chemical analysis. In April of 2021 Joe began working for Greenleaf labs in Poteau, OK and has brought years knowledge and leadership to our laboratory.

Christopher Daniels
Laboratory Analyst
Christopher Daniels

Christopher Daniels is a Laboratory Analyst with a bachelor’s degree in Medical Technology and 17 years of experience working in hospital laboratories. His background in clinical testing brings a strong foundation in accuracy, quality control, and patient safety to his work in cannabis analysis.
He transitioned into the cannabis testing industry to be closer to home following the birth of his child, who required an extended NICU stay after being born at 25 weeks. That experience reinforced his commitment to careful, reliable laboratory work and the importance of trust in test results.
Outside the lab, Christopher enjoys tabletop role-playing games, board games, and horror films.

Devin Thompson
Laboratory Analyst Assistant
Devin Thompson

Devin Thompson has worked across the cannabis industry, gaining experience at both a cultivation facility and a dispensary before joining Greenleaf Labs several years ago. He began in sample intake and now supports laboratory operations as a Laboratory Analyst Assistant. Outside of work, Devin enjoys watching football and cheering on the Kansas City Chiefs.

Kalya Davila
Laboratory Analyst Assistant
Kalya Davila

Kayla Davila is a Laboratory Analyst Assistant specializing in microbiology, where she supports laboratory operations, data analysis, and quality processes to ensure accurate and reliable results. She holds an Associate of Science in Biology from Carl Albert State College and brings a strong foundation in microbiology and laboratory sciences.

Kayla is detail-oriented and passionate about scientific precision, contributing to efficient workflows and dependable outcomes. Outside of the laboratory, she enjoys reading, baking, and gardening.

Jerrett Demory
Laboratory Intake / Transport Driver
Jerrett Demory

Jerrett Demory brings several years of cannabis industry experience to Greenleaf Labs, having owned a dispensary for four years and managed another prior to joining the team. He initially served as a Transport Driver and later transitioned into sample intake and preparation, supporting daily laboratory operations. In his current role, Jerrett serves as a Laboratory Intake/Transport Driver and provides backup driving support as needed.

Grant Thompson
Transport Driver
Grant Thompson

Grant Thompson has been with Greenleaf Labs for three years. He began his role in the office supporting order creation and administrative functions before transitioning into transport, where he helps ensure reliable and timely sample delivery. Grant enjoys spending time outdoors and values his Christian faith.

James Melson
Transport Driver
James Melson

James Melson has been a transport driver with Greenleaf Labs for three years, ensuring the safe, secure, and reliable transport of samples. He plays a vital role in maintaining chain-of-custody standards and supporting daily laboratory operations. Outside of work, James enjoys football, motorsports, and spending time outdoors.