335. A facility dewaters its underground mine and injects the water into a well on-site. Are the amounts of listed toxic chemicals injected considered a release to land, or are these amounts exempt under the ‘use of toxic chemicals present in process water and non-contact cooling water as drawn from the environment?’ The water is not used, nor is it considered process water or non-contact cooling water.
No. The exemption for toxic chemicals contained in water drawn from the environment or from municipal sources is provided for the use of water containing these chemicals in processes and for non-contact cooling purposes. The facility is not otherwise using the water drawn from the underground mine, and therefore, the intake water exemption does not apply. The facility is simply disposing of the water containing listed toxic chemicals as drawn from on-site, and therefore, the facility is not manufacturing, processing, or otherwise using these chemicals. These amounts would not count toward thresholds. However, the facility is disposing of these chemicals and if a threshold is exceeded elsewhere at the facility for one of the same chemicals, then the facility would be required to count amounts injected as released.