The initial notifications for existing sources subject to the Boiler MACT are due by May 31, 2013. EPA promulgated the final amendments to the Boiler MACT (40 CFR 63 Subpart DDDDD) on January 31, 2013. Initial notifications for existing sources are due within 120 days of this date, or May 31, 2013. A boiler or process heater is considered existing if construction commenced on or before June 4, 2010. Facilities with boilers or process heaters that achieved startup after June 4, 2010 but before January 31, 2013 must also submit an initial notification by May 31, 2013. Facilities with boilers or process heaters that achieve startup on or after January 31, 2013 must submit initial notifications within 15 days of the unit’s startup date.
EPA has recently released a template: http://www.epa.gov/airtoxics/boiler/imptools/majorinotificationofapplicability.docx.