A metal mining facility receives ash that it directly incorporates in concrete which it then uses on-site to form cement blocks. Is this direct use of ash eligible for the de minimis exemption?
The use of ash as a component of a mixture (concrete) that is otherwise used on-site to construct cement blocks constitutes an otherwise use of a material containing listed toxic chemicals and such amounts must be counted toward the facility’s otherwise use of those chemicals. In this case, the ash is not considered a waste because it is not managed as a waste. Thus, the listed non-PBT chemicals contained in the ash are eligible for the de minimis exemption if they do not exceed the de minimis concentrations. Additional guidance regarding the de minimis exemption can be found in Directive #2 of the Addendum to 1998 Question and Answer Document and the Revised 1998 EPCRA Section 313 Questions and Answers Document.