In April 2010 Dallas County Health and Human Services (DCHHS) staff investigated reports of acute-onset dizziness among patrons in a local restaurant. Symptoms included fainting resulting from low blood pressure, occurred within minutes of consuming food from the restaurant. Five patients who visited the restaurant separately over a 4-5 hour period. All five consumed iced tea from paper cups filled from a self-serve urn. Samples of the ice tea and paper cups from ill patients were analyzed by an FBI laboratory. The lab detected hydrazoic acid which is formed when sodium azide contacts water. The mechanism by which the tea became contaminated with sodium azide remained unknown. All five patients recovered.