by Joseph Noferi, Edward R. Arling, Ralph L. Dillon, and Mikael Blomqvist, Pharmacia An FDA Warning Letter can be a business disaster. This case study tracks a company from receipt of an FD 483 ? that did not find contamination, but only the potential for contamination ? to 18 months later when the facility received a clean bill of health. What it did to get there ? and what it learned ? may keep your site from losing its operating freedom.