The EPA is taking direct final action to amend the National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry. This direct final rule provides a compliance alternative for sources that would otherwise be required to use a hydrogen chloride (HCl) continuous emissions monitoring system (CEMS) to demonstrate compliance with the HCl emissions limit. This compliance alternative is needed due to the current unavailability of the HCl calibration gases used for CEMS quality assurance purposes.