Abstract: At approximately 11:30 p.m. on October 2, 2007, the operator of the batching machine was "cooking" a batch of ZEBA, an absorbent soil amendment, when an un-reacted acrylonitrile entered the batching process and escaped from the "clam shell" into the work area. Three employees were exposed to acrylonitrile. One employee suffered from throat irritation, watery eyes, and mild breathing difficulty. All three employees were sent to the emergency room and were examined by the ER physician, and released to work without treatment in less than an hour. All the employees' symptoms had subsided by the time they left the hospital. The three employees subsequently returned to work and were told to go home until the plant was safe.