591. A mining facility stores coal or ore outside. One or more listed toxic chemicals are contained within the storage piles. Due to exposure and weathering influences, other listed toxic chemicals are manufactured in the storage piles and may subsequently run-off onto land or surface water. How should the facility consider the manufacturing of listed toxic chemicals within a storage pile?
Amounts of listed toxic chemicals known to be manufactured on-site from the storage of raw materials, mixtures, or trade name products must be considered toward the manufacturing threshold for those chemicals. The term manufacture means 'to produce, prepare, import, or compound a toxic chemical.' If the mining facility has knowledge that a listed toxic chemical is manufactured on-site, the facility should count the amount of the listed toxic chemical manufactured toward the manufacturing threshold.