Guillermo Garcia | Principal, Chief Executive Officer

Guillermo Garcia co-founded GSG in 1992, leading the transformation of GSG from a small environmental services company into a multi-faceted consulting firm specializing in engineering, environmental and construction management services. As CEO of the company, he has fostered growth through his leadership, vision, and participation in an expanding array of markets.

He has 25 years of experience in the industry and has worked extensively with the City of Chicago including the Chicago Public School (CPS) system, the Public Building Commission (PBC), and the Chicago Housing Authority (CHA). He is an active member of the Hispanic American Construction Industry Association and currently sits as the Chairman of the Board of the Illinois Hispanic Chamber of Commerce.

read more

Arturo Saenz | Principal, Chief Operating Officer

As Chief Operating Officer, Arturo Saenz is responsible for designing, improving, and assuring system-wide implementation of the policies and procedures that allow GSG to efficiently deliver services. He has 18 years of experience in environmental engineering, business development, and strategic planning, and provides direction and structure for operating units within GSG. Arturo has led corporate, federal, state, and local government environmental programs including those owned and managed by the Federal Aviation Administration (FAA), Illinois Capital Development Board (CDB), Chicago Housing Authority (CHA), and Chicago Public School (CPS) system.

read more

Ala E. Sassila, Ph.D., P.E. | Principal, Chief Engineer

Dr. Ala Sassila has 25 years of experience in environmental remediation, construction management and inspection, and geotechnical engineering. As Chief Engineer, he leads GSG’s engineering operations, analyzing the technical feasibility of projects, coordinating client requirements with technical and regulatory specifications, and making final decisions upon technical matters.

Ala specializes in leading large multidisciplinary teams of engineers and scientists in the implementation of infrastructure management programs. His experience includes the Midway Airport Terminal Redevelopment Program, the Terminal 6 Building and Underground Utility Bank Reconstruction Program at O’Hare International Airport, Pavement and Toll Plaza Building Improvements for the Illinois State Toll Highway Authority, and obtaining “No Further Remediation” letters for more than 50 public building projects in the State of Illinois.

read more

Jigar M. Shah, M.S., CIH, CSP | Industrial Hygiene Practice Lead

Jigar Shah is a Board Certified and Licensed Industrial Hygienist and Safety Professional with 14 years of experience and is responsible for implementation of GSG’s Industrial Hygiene services. His practice focuses on the assessment of worker safety and personal protection, management of hazardous building materials during construction, and the development of administrative and engineering controls to eliminate unsafe working conditions and unacceptable public environmental impacts.

Jigar is highly experienced in the assessment and abatement of hazardous building materials including asbestos, lead-based paint, mold, radon, and mercury, as well as monitoring of community air quality and construction noise impacts. His services support maintaining regulatory compliance regarding safety and health of workers, employees and the public during planned infrastructure improvements as well as responding to employee and worker complaints and legal enforcement orders.

read more
Page 1 of 212

Join our newsletter

Please register for our newsletter to receive information about GSG.

join now

Follow us on:

Contact Us

Chicago HQ
  • 2942 W. VanBuren, Chicago, IL 60612
  • (312) 733.6262
  • (312) 733.5612

Contact us


* indicates required