On February 15, 2002, Olin disclosed potential PSD and NSPS violations at the facility's East Alton, Illinois casting plant. On April 10, 2002, Olin submitted a follow up letter with more detailed information on the potential violations. Subsequent to this disclosure, the facility upgraded the casting plant again and the Illinois EPA evaluated those upgrades in relation to PSD and the proper permits were issued in 2004. Furthermore, the facility has always had baghouses in place at the casting plant. After disclosing the potential violations, Olin conducted NSPS opacity testing and demonstrated compliance with the 10 percent opacity limit. Therefore, in September 2008, EPA issued a letter to Olin stated that no more actions would be taken by EPA in regard to the specific violations disclosed in the February 15, 2002 self-disclosure letter.