42 Technical services, namely, engineering studies, conducting economic feasibility studies and technical feasibility studies, conceptual and detail design for others of processing facilities, buildings and other structures, in the fields of threat reduction, defense infrastructure, environmental remediation, nuclear processing, power generating, mining, manufacturing facilities, railway systems, highways and bridges, airports, dams, hydroelectric plants, hazardous waste, high hazard facilities, chemical agent disposal and geologic evaluation Technical services, namely, engineering studies, conducting economic feasibility studies and technical feasibility studies, conceptual and detail design for others of processing facilities, buildings and other structures, in the fields of threat reduction, defense infrastructure, environmental remediation, nuclear processing, power generating, mining, manufacturing facilities, railway systems, highways and bridges, airports, dams, hydroelectric plants, hazardous waste, high hazard facilities, chemical agent disposal and geologic evaluation