This action involves a continued approval of an alternative monitoring method to the Portland Cement Industry direct final rule, which was originally intended as a short-term solution to a timing issue relative to compliance demonstrations. In July 2016, when this alternative monitoring method was first published (via a direct final rulemaking), it was believed that hydrogen chloride (HCl) calibration gases would become available within a period of one year (i.e., the rule provides for the use of this alternative monitoring method until July 25, 2017). The calibration gases are needed for compliance demonstrations relative to the HCl continuous monitoring requirements of the Portland Cement Industry final rule. However, as the one-year deadline approached, it became apparent that the calibration gases wound not be widely available for operators, and when the date that the calibration gases would become readily available was uncertain. For this reason, we developed a direct final rule/parallel proposal to extend the alternative monitoring method until such time when the calibration gases became available. (Note that this change will affect only kilns that do not have HCl controls, which are required to continuously monitor for HCl.) The direct final rule/parallel proposal included an alternative method for HCl compliance that requires a yearly stack test along with the HCl monitors performing as parametric monitors instead of direct continuous monitoring. The direct final/parallel proposal was published on June 23, 2017. It was believed that the action would not receive any adverse comment from the public, but on June 29, 2017, we received adverse comment from EarthJustice. Due to the shortened comment period of the direct final/parallel proposal, we were unable to withdraw the direct final in a timely manner. We have now published a final rule to restore the National Ambient Air Quality Standards (NESHAP) to the conditions that existed prior to the direct final amendments. In addition, we have re-proposed the alternative monitoring method with the intention of allowing additional time for the public to comment. After opportunity for the public to comment, we will take final action considering all comments received on the proposal, and the comments that were received from the direct final and parallel proposal published on June 23, 2017.