> ENVIROTECH ENGINEERING & CONSULTING INC Oklahoma Since: 1992 ENVIROTECH ENGINEERING & CONSULTING INC
> DIVERSIFIED CONSTRUCTION OF OKLAHOMA, INC. Oklahoma Since: 1989 DIVERSIFIED CONSTRUCTION OF OKLAHOMA, INC.
> ERNEST C. ANDERSON GRAVEL & READY MIXED, INC. Minnesota Since: 1972 ERNEST C. ANDERSON GRAVEL & READY MIXED, INC.
