Team

Driven by leaders with a cohesive vision and strong entrepreneurial spirit, the company has evolved into a diverse environmental, engineering, and construction services firm. Since 1997, ERRG has rapidly grown to a team of nearly 300 employees based in strategic locations throughout the continental United States, Hawaii, and Guam.

Directors

Cynthia Liu, PE
President and CEO

Bradley Hall, PG, PMP
CTO and Vice President

  • Ms. Liu is ERRG’s President and CEO responsible for company-wide business management, engineering oversight, as well as selected program and project management. She works with clients and agencies to develop effective solutions for site remediation and closure.  Her background includes investigation, remedy selection, and implementation of remedial systems for addressing contaminants in complex environments.  She works closely with clients and stakeholders to proactively drive environmental cleanup and restoration projects to successful completion.   Ms. Liu is heavily involved with developing business for munitions response under CERCLA and environmental compliance and restoration throughout the Pacific Rim.

  • Mr. Hall is ERRG’s Chief Technical Officer and Vice President responsible for oversight and technical quality review of all projects, including project planning, field execution, and all deliverables. He has  construction, site assessment, remedial action, and information technology experience. Mr. Hall also serves as ERRG’s Program Manager for several large Indefinite Quantity/Indefinite Delivery contracts for clients including the U.S. Navy and U.S. Army Corps of Engineers.

Rowan Tucker
Vice President of
Remediation Services

David Tang, PE, GE
Principal Engineer

  • Mr. Tucker is ERRG’s Manager of Remediation Services responsible for remediation project oversight, health and safety, emergency response, and waste disposal coordination. Mr. Tucker has extensive experience in the environmental and hazardous waste management industry.

  • Mr. Tang is experienced in the field of civil and geotechnical engineering and construction management. His specialties include civil design, grading and excavation planning, drainage design and calculations, geotechnical field investigations and laboratory testing programs, seismic response analysis, static and seismic slope stability analyses, settlement analysis, liquefaction analysis, landfill cap infiltration computer modeling, and material evaluations. Mr. Tang also has extensive experience in field construction quality assurance/quality control of landfill lining systems, deep and shallow building foundations, and complex ground improvement projects using vibrofloatation, deep dynamic compaction, and chemical grouting.

Randy Randall
Vice President of Operations

  • Mr. Randall has a broad base of experience in the environmental field. His background includes extensive health and safety, site assessment, emergency response, and federal Superfund removal action project management experience. For several years Mr. Randall was a dedicated contractor to the U.S. Environmental Protection Agency in Region 9.

Corporate Leadership

Kim Jackson
 Chief Financial Officer

  • Ms. Jackson manages ERRG’s finance and contract functions and has extensive experience providing finance, contract, accounting, and tax services.  Her responsibilities include implementing processes, procedures, and reviews that significantly improve operations, including adhering to federal and state regulations, while reducing ERRG’s exposure to risk.  Ms. Jackson also has expertise in the administration of all contract types (firm-fixed price, time and materials, and cost-plus). 

Heather Wollenburg, PMP, CSP, CIH
Corporate H&S Manager

  • Ms. Wollenburg has been with ERRG since 2007 and was more formally incorporated into ERRG’s Safety Department in 2017 as the Corporate H&S manager for DoD projects.  She works with the directors to develop and implement compliant programs for the company.  She manages all aspects of corporate and project health and safety.  She works with designated Regional Safety Coordinators and Site Safety Officers located throughout the company to implement and administer the company’s safety program at a regional and project level.  Ms. Wollenburg reviews site-specific safety documents, oversees the safety training program, and works to ensure compliance with requirements at local, state, and federal levels. 

Melissa Grasso
Business Development Manager

  • As ERRG's Business Development Manager Ms. Grasso is responsible for identifying, tracking, evaluating, and closing new business opportunities. She works closely with internal and external stakeholders to formulate and implement marketing and business development strategies and identify key clients and pursuits, including oversight of client and teaming partner relationships.  

Regional Managers

Dan Lohr, PG
Bay Area

  • Mr. Lohr is a Senior Project Manager and Professional Geologist with experience working under Federal, state, and local laws and regulations and guidance under RCRA/CERCLA programs. Mr. Lohr’s experience covers a wide range of environmental services including remediation, investigation, assessment, construction, and compliance. Mr. Lohr has experience working with multiple stakeholders including regulatory agencies, local municipalities, community groups, and businesses. Mr. Lohr is dedicated to safety, with no lost time incidents on projects managed/overseen throughout his career. 

Scott Pringle, PhD
Southern California

  • Mr. Dwyer is a Senior Project Manager with experience in construction, environmental remediation, and site restoration. His work history encompasses a wide range of clients and projects in the public and private sectors.  Mr. Dwyer manages environmental remediation and construction projects, specializing in complex design/build and site restoration projects in the government, public and private sectors.  He has extensive experience in both construction management and project management roles on complex projects involving a high degree of regulatory oversight, and managing design teams, regulatory approval efforts and field construction activities in design/build and design/bid/build project delivery approaches.

  • Dr. Pringle is ERRG’s Regional Manager responsible for business operations in the southern California and Texas geographical regions. He has 25 years of environmental/remediation construction experience in both the federal and non-federal business sectors. Mr. Pringle strives to build strong technical and management teams within these regions to meet customer expectations and project and program performance objectives.

Tom Mills, PG
MEC

  • As ERRG’s Guam Regional Manager, Mr. Applegate is focused on MMRP investigations and Environmental Remediation projects for NAVFAC, AFCEC, and USACE, as well as commercial clients in the Marianas and Indo-Pacific region. A Retired U.S. Army EOD Technician and former Intelligence Professional, he has experience managing CONUS and OCONUS military and civil projects and conducting explosive remediation actions on five continents. Mr. Applegate is qualified by the DoD to operate at all Unexploded Ordnance (UXO) levels and is a SME in the integration of military construction projects and MMRP investigations. 

Steven Applegate
Guam

Matt Dwyer
Sacramento

  • Mr. Mills is a geoscientist with experience in the areas of CERCLA and RCRA investigations. As ERRG’s Munitions Response Division Manager, he has extensive experience conducting Military Munitions Response Program (MMRP) investigations using geophysical investigations. Mr. Mills is a subject matter expert in munitions constituent sampling and has developed and authored multiple standard operating procedures for environmental field procedures.  Mr. Mills is highly proficient in the areas of technical approach development and planning, field operations management, environmental and geologic sample and data collection, analysis and data evaluation, and technical writing.  Mr. Mills manages large MMRP projects for the USACE, U.S. Navy and commercial clients.