By law, American-made iron and steel foundry products must be used in all federal transportation projects and state and local government projects that use federal transportation dollars. Products covered by the law include manhole frames and covers, catch basin frames and grates, iron and steel inlet grating, and various miscellaneous iron products. 

The Buy American provision of the law, known as the Intermodal Surface Transportation Efficiency Act of 1991, explicitly requires that iron castings manufactured in U.S. foundries be used for federal transportation infrastructure projects. Such a provision first appeared in the Surface Transportation Assistance Act of 1982. Then, however, the law required that only U.S.-made "steel and manufactured products" could be used in transportation projects funded by the federal government. 

With the passage of the 1991 legislation, Congress clarified the 1982 legislation by specifically stating that iron products are covered by the Buy American provision. The Department of Transportation Buy American provision now reads U.S.-made "steel, iron and manufactured products."