Imagine this scenario, you need to bring in a backup emission unit or control device to operate while planned or unplanned maintenance work is completed on an existing emission unit or control device. The backup unit is either the same size or smaller than the existing unit and will only be operated while the existing unit is out of service. For many facilities, this is not an uncommon scenario and the current Indiana Department of Environmental Management (IDEM) air permitting regulations do not include a permit exemption in 326 IAC 2-1.1-3 for these backup units. If a facility needs to bring a backup unit onsite to operate in place of an existing permitted unit they must submit a registration or permit application for approval prior to bringing the unit onsite, if the backup unit requires a modification to the registration or permit. IDEM is considering changes to 326 IAC 2-1.1-3 to include a permit exemption for short term backup emission units or control devices used as part of normal operations while maintenance is completed on the existing emission unit or control device. The proposed rule change could allow a facility to bring short term backup units onsite without prior approval.

The first notice of comment period for this proposed rule change ended August 19, 2016. It is anticipated the proposed rule change will go to second notice of comment period some time in 2018. Additional information on the status of the rulemaking and a copy of the first notice can be found on IDEM's website.