Columbia subject headings:
Metal trade--Waste disposal--Government policy--United States.
Water--Pollution--Prevention--Government policy--United States.
Harvard subject headings:
Metal trade--Waste disposal--Government policy--United States.
Water--Pollution--Prevention--Government policy--United States.
Princeton subject headings:
Metal trade--Waste disposal--Government policy--United States.
Water--Pollution--Prevention--Government policy--United States.