Because combustion normally does not represent effective treatment of these wastes, such burning can be considered impermissible dilution. In such cases, these hazardous metal-bearing wastes cannot be combusted legally. This Policy Statement clarifies the general situation regarding combustion of these metal-bearing hazardous wastes, but application of this policy will vary depending on particular circumstances. Hazardous constituents are not destroyed, removed or immobilized if they are diluted.
Impermissible dilution can occur under a number of circumstances.
The most obvious is when solid wastes are added to a prohibited waste to reduce concentrations but not volumes of hazardous constituents, or to mask their presence. EPA is providing guidance today clarifying how the LDR dilution prohibition could apply to certain inorganic metalbearing hazardous wastes that may be placed in combustion units, other than metal recovery furnaces. This memorandum deals with the question of whether combustion of prohibited inorganic hazardous wastes can be a type of impermissible dilution. Thus, impermissible dilution may result when these wastes are combusted. Characteristic wastes, of course, cannot be generically characterized as easily as listed wastes because they can be generated from many different types of processes.