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Our Team


Sean Griswold


Sean calls Durango, Colorado, home, and he lives with his wife and three kids. He is the first employee of Sierra Chemicals, which started in July 1994. Sean purchased Sierra Chemicals in 2005. He hopes to lead in his position as president with empathy and insight from 27 years of industry experience.

Shedrick Lewis

VP of Operations

Shedrick has over 25 years of service in the industrial cleaning industry and has held many roles within safety, sales and operations). Shedrick enjoys the outdoors and spending time with family and friends. He studied business administration – general business at Lamar University.

David Navarrete

VP of Sales

David is responsible for the overall sales division and sales team across the country. David lives in Grand Prairie, Texas, with his family. David has been with Sierra since 2017 and is always available for questions or direction on planned projects. When he is not working, he enjoys spending his time with his wife, Shea, and his daughter, Lourdes. Besides his passion for helping customers find solutions, fitness and family are David’s passions.


Jory Snider

Safety Director

Michael Nichols

Safety Specialist

Michael holds a Bachelor’s degree in Industrial Safety from the University of Central Oklahoma. With 3 years of experience in the field, Michaels has dedicated his career to ensuring safety in various environments. Beyond work, Michael enjoys spending quality time with his wife, Nancy, and spending time with family. He finds relaxation in playing golf and watching OU football. 


Brian Veitz

Field Service Sales Zone 2 – North Dakota

Brian is the sales representative for the Williston Basin area and beyond. He holds a Bachelor of Science in physics and has more than eight years of oil and gas experience.

Josh McCoy

Field Service Sales Zone 4 – Permian Basin, West Texas, Eastern New Mexico

Josh McCoy graduated from Texas A&M University. He started his career in oil and gas with Sierra Chemicals in 2004 and spent the next 9.5 years chasing gas plants and compressors all over the US. He then worked in many aspects of the oil and gas industry: drilling and solids control, plugging and abandonment, workovers, completions and coil tubing, re-entry projects and whipstocks, fracking and surface equipment, SWDs and water management. He also has had many roles in sales and operations throughout his career before returning to Sierra Chemicals.

Matt Miller

Field Service Sales Zone 7 – North Texas, South Oklahoma And North Louisiana

Matt has been with Sierra Chemicals almost three years. He draws on our excellent safety team, operations team and administrative staff to bring clear and comprehensive solutions to customers’ needs. When he’s not working, he enjoys spending time with family and friends and all types of outdoor activities, sports and competition.

Mike Kennemer

Field Service Sales Zone 3

Mike joined the Sierra Team in July of 2022. He has been working in the oilfield since he graduated from OSU. He cleaned his first rank as summer help during college in 1977. Mike has experience in production chemicals, chemical manufacturing, chemical sales, chemical cleaning and industrial cleaning. He loves meeting new people, Jesus, his wife and kids.

Francois Therrien

Field Service Sales Zone 8 – Pennsylvania, West Virginia, Ohio, Kentucky

Francois has been with Sierra Chemicals since January 2022. He received his bachelor’s degree in Geophysics from the University of Akron. When Francois is not working, he enjoys spending time with his family, watching movies and Football.

Daniel Waer

Account Manager- Zone 5

Daniel joined Sierra Chemicals in April 2022. He graduated from the University of North Texas with a BBA in Organizational Behavior and Human Resources. Upon graduation, he returned home to Goliad, Texas and started his career as a teacher and coach before he entered the Oil and Gas Industry. Daniel has worked in the Oil and Gas Industry for the past 8 years, specializing in Gas Compression and chemical services. Daniel currently resides in Refugio, Texas. During his free time, he and his family love to travel.


Huber Ortega

Lead Foreman

Huber’s areas of expertise are safety, project management, supervisory skills and quality control. He provides leadership and mentoring to his crews. Huber also likes fishing and riding his motorcycle. When he is not working or doing his personal hobbies, he loves spending time with his family and dogs.

KJ Choi


KJ has a Bachelor of Science in Construction Management and an associate degree in administration of justice. He is also a welding instructor for classrooms and fields. When not working, he loves traveling with his wife and fishing.

Albino Flores


Albino’s areas of expertise include quality control, problem solving and project management. His mission is to provide exceptional customer service. His hobbies include building Lord of the Rings miniatures and landscapes and playing Yu-Gi-Oh. Albino also loves spending time with his four sons and grandchildren.

Robert Harrison


Robert has been with Sierra Chemicals for a total of 5 years and resides in Lubbock. He received his bachelor’s degree in Business from Southern New Hampshire University. When Robert is not working, he enjoys spending time with his wife and kids coaching basketball.

Calvin Alexander


Calvin has been with Sierra Chemicals for over 2 years. He currently resides in Marian, TX. When Calvin is not working, he is spending time with his wife and son. He enjoys reading, watching movies, and deep intellectual conversations.

Ledie Gutierrez


Ledie has been with Sierra Chemicals since February 2022. Prior to joining our team, Ledie was a Field Supervisor at Evergreen Chemical. When Ledie is not working, he enjoys playing with his dog, disc golf and mountain biking.

Justin Lewis

regional operations MANAGER

Jesse started with Sierra Chemicals in November of 2022. He was born and raised in Ponca City, Oklahoma. During Jesse’s free time he enjoys spending time with his family and friends as well as watching Oklahoma State and the Pittsburg Steelers. When asked what Jesse loves most about working for Sierra Chemicals he said, “Learning something new and how supportive everyone is”.


Pam Vandervalde


Pam has been with Sierra Chemicals for 15 years. Pam manages accounts receivable, accounts payable, payroll and accounting functions. Pam has a bachelor’s degree in accounting from New Mexico State University and has been working in accounting for 20 years.

Janet Ruper

Administrative Assistant

Janet recently graduated from Fort Lewis College in Durango, Colorado, with a bachelor’s degree in business administration. She is originally from a small town in New Mexico, Peralta. She and her family moved to Durango, Colorado, about six years ago. She has four children, three of which are young adults. In her spare time she enjoys baking and spending time with her youngest child, who is eight. She loves bike rides, snowboarding, building forts, movie and game nights and just spending time with her family.

LaDonna Cooperwood

HR Administrator

LaDonna has more than 10 years of human resources, recruitment, team building and project management experience. She graduated with an MBA from Grand Canyon University in Phoenix and earned a Bachelor of Science from the University of Mississippi. She is the mother of two daughters and the wife of a sports fanatic. She loves spending time with her family, traveling, exploring new places, and enjoying the simple things in life. She was born and partially raised in Chicago until she moved to Mississippi. LaDonna takes pride in all things human resources and impacting employees’ experiences within the company.

Savannah Redwine

Marketing/Sales Coordinator

Savannah is originally from Friendswood, Texas and now lives in Lubbock. She graduated from Texas Tech in 2018 with her Bachelor of Arts in Public Relations and is also a Texas Tech Cheer Alum. She has 3 years of marketing experience and started working with Sierra Chemicals in March 2022. When Savannah is not working, she enjoys spending time with her husband and their three labradors.

Tiffani Bonds

Business manager

Tiffani has over 20 years of experience in Business Administration, Management and Project Management spanning over the oil and gas, computer and entertainment industries. She hails from the Houston, TX area and graduated from the University of Houston in 2006. She lives with her husband and 3 kids and enjoys baseball (Go Astros!) and being outdoors.