The Defense Base Act covers civilian workers who:
- Work for private employers on U.S. military bases or on any lands used by the U.S. for military purposes outside of the United States
- Work on public work contracts with any U.S. government agency, including construction and service contracts in connection with national defense or with war activities outside the United States
- Work on contracts approved and funded by the U.S. under the Foreign Assistance Act, which among other things provides for cash sale of military equipment, materials, and services to its allies, if the contract is performed outside of the United States
- Work for American employers providing welfare or similar services outside the United States for the benefit of the Armed Services, e.g. the United Service Organizations (USO)
If any one of the above criteria is met, all employees engaged in such employment, regardless of nationality are covered under the Act.