heavy metals and, therefore, is subject to regulation as a hazardous waste in accordance with
Federal and state hazardous waste management regulations.
The concentration of hazardous contaminants in spent engine coolant seems to depend
on many factors, including: the maintenance and use of the vehicle, the design of the
engine, and the amount of corrosion inhibitor additives. The amount of heavy metals in
spent coolant should greatly decrease in the next few years because of a trend in the
automotive industry to use aluminum and plastic radiators rather than brass. Use of plastic
and/or aluminum parts reduces or eliminates the need for lead solder, thereby reducing or
removing the source of lead and copper contamination. This industry trend may reduce, if
not eliminate, the issue of contaminated engine coolant and disposal as a hazardous waste.
Spent engine coolant can be recycled by removing contaminants and breakdown
products of the original ingredients and replacing corrosion inhibitors. Generators of spent
engine coolant can either purchase equipment to reclaim the fluid themselves or contract with
an engine coolant reclaimer.
8. Blast Furnace Slag
In the proposed CPG, EPA incorrectly characterized iron blast furnace and ground
granulated blast furnace slag (GGBF slag), giving the impression that all iron blast furnace
slag is ground granulated. Based on comments submitted by the U.S. Bureau of Mines and
EPA's `Report to Congress on Special Wastes from Mineral Processing," EPA is providing
corrected information in this section.
Iron blast furnace slag is a by-product of the production of iron in a blast furnace.
Approximately 16 million tons of iron blast furnace slag are generated annually and are not
reused within the original manufacturing process. In the U.S., molten slag is cooled and
solidified by one of three processes, which result in either air-cooled, expanded, or
granulated slag. Approximately 90 percent of all iron blast furnace slag is air-cooled.,
According to the U.S. Bureau of Mines, 14.1 million metric tons of iron blast furnace slag
were sold or used in 1992 (12.7 million metric tons of @-cooled, and 1.4 million metric
tons of expanded and granulated slag).
Approximately 75 percent of iron blast furnace slag is used in aggregate applications
such as fill and road bases. Granulated slag can be ground and used in the manufacture of
cement, although it also is used as fill and road bases, as aggregate for concrete products,
and for soil conditioning.
"Report to Congress on Special Wastes from Mineral Processing," Volume II:
Methods and Analyses, U.S. Environmental Protection Agency, Office of Solid Waste, July
1990, Chapter 8.