On September 5, 1996, the EPA issued the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Group I Polymers and Resins (61 FR 46906), and on September 12, 1996, the EPA issued the Group IV Polymers and Resins NESHAP (61 FR 48208). This action corrects an error in the final Group I Polymers and Resins NESHAP, by extending the compliance date for heat exchange systems. In addition, this action extends the compliance date for equipment leaks for both the Group I and Group IV Polymers and Resins NESHAP, to allow time necessary for affected sources to respond to the amendments to the hazardous organic NESHAP (HON) equipment leak provisions promulgated on December 26, 1996, which are directly referenced in both subparts U and JJJ.