The LEHDER company name comes from the surnames of the original four principals: Sid Lethbridge, Des Hayles, Mike Denomme and Mark Roehler. There are now a total of seven Principals at LEHDER: Daryl Zander joined the team when AirWorks Environmental, located in Edmonton, Alberta merged with LEHDER in April 2000 to form the Western Division of LEHDER. Peter Pakalnis became the sixth Principal at LEHDER In March 2003. In August 2005 Marnie Freer was appointed as Principal.

Mr. Lethbridge is a Chemical Engineer with over thirty years of experience in environmental management and chemical process development. The projects he has managed and conducted include emission inventory development, air dispersion modeling studies, industrial site assessments; site remediations; environmental audits; preparation of permit applications and facilitation of the approval process (Ontario, Quebec, Alberta); development of air pollution control equipment; odour evaluation studies of industrial plants; and acquisition and divestiture due diligence programs. He was a major contributor to a chemical research and development program which culminated in the construction and commissioning of a commercial foam insulation product.   

Mr. Hayles is a professional engineer with over twenty years of experience in environmental engineering and IT technology. He has managed environmental projects in several areas including: site remediation: process development for pollution control equipment design and construction; environmental compliance audits; site and facility audits for acquisition and divestiture due diligence programs; and development of environmental management systems and permit development for operations in Ontario, Quebec and Alberta. His background includes experience in the automotive industry as a process engineer and in a chemical research and development facility and IT Management for LEHDER.     

Mr. Denomme has over thirty years of experience in the environmental management field. His experience includes environmental audits, source and emission inventories, dispersion modeling and the acquisition of facility operating permits. He has particular technical expertise in industrial source emission testing and has directed and managed hundreds of stack sampling projects at industrial locations throughout North America. He is the Director of the LEHDER Emissions Testing Team in Sarnia, one of the largest and most experienced in Canada.  

Mr. Roehler has over thirty years of experience in environmental management and chemical research and development. The projects he has managed and conducted include: environmental stewardship, industrial site assessments, source emission surveys, personal and area exposure sampling, environmental audits, WHMIS, material safety data sheets and transportation regulations for dangerous goods and wastes. Mr. Roehler has developed and taught environmental courses at the request of Lambton College in Sarnia, Ontario and the Centre for Health Environment & Safety (CHES), formerly the Environmental Management Resource Centre for Business (EMRCB) in London, Ontario, in the following disciplines: TDG, dangerous goods air regulations, waste generation and transportation (Reg. 347) and environmental auditing.

Mr. Zander has over 13 years of experience in the area of environmental management and testing gained through assisting clients with a wide variety of environmental issues. Daryl manages and conducts projects to audit activities and facilities in the upstream oil and gas sector; measures emissions of various pollutants as required by Approvals and Operating Permits; evaluates process parameters to improve efficiencies or operation of various processes; determines efficiency and conducts performance guarantee testing of pollution control devices.

Mr. Pakalnis is an Environmental Technologist with twenty years of experience in the source testing field. Peter has managed and conducted hundreds of stack monitoring programs in numerous industrial sectors for both compliance and process testing purposes. Peter also has vast experience in conducting CEMS RATA's. Since 1996 Peter has been teaching the stack monitoring portion of the sixth semester ENVR 5006 air monitoring course at Fanshawe College in London, Ontario. Peter is also a Qualified Source Testing Individual (QSTI) for Groups I and III.

Mrs. Freer has fifteen years of environmental consulting and project management experience. She is a member of the Modeling Practitioner Group providing technical input to the MOE for the implementation of O.Reg.419. The projects she has managed and conducted include emission inventory development, air dispersion modelling and air approvals; population and implementation of database systems; creation of algorithms for MSDS authoring software; TDG and WHMIS training programs; and workplace exposure monitoring.