On Friday, February 19, 1999, a devastating explosion destroyed a plant operated by Concept Sciences, Incorporated (CSI) in Hanover Township, Pennsylvania. Hanover Township is located in Lehigh County near Allentown. The blast killed five people, caused approximately $5 million in damages, and disrupted electrical service to approximately 1,188 PP&L customers. All of the victims were men between the ages of twenty-five and fifty-five. Four of the deceased were CSI employees and died from the effects of the massive explosion. The fifth victim, an employee of a business located next to the CSI facility, died as a result of a severe head injury from flying debris. One of the deceased CSI employees was a member of an area volunteer fire company.

Fourteen people, including five firefighters, were transported to area hospitals during the incident. The most severely injured were two CSI employees who were buried beneath debris. They were rescued by firefighters more than one hour into the incident. Firefighter injuries included chemical burns, chest pains, lacerations, strained muscles, and shortness of breath.

The explosion registered 0.7 on the Richter Scale at Lehigh University’s seismograph center, which is located approximately five miles from the site in Bethlehem. The University’s readings indicate that the explosion occurred at 20:14:43 hours and caused the ground to move both up and down and side to side. The explosion could be seen for seven miles and could be felt as far away as Lehighton and Tobyhanna to the north and Trexlertown and Longswamp Township to the west. There were numerous reports of windows being blown out of homes on Dauphin Road and Irving Street in Hanover, Township.

The explosion produced a white cloud that rained chemical residue onto the streets of Allentown, approximately two miles from the blast site. An evaluation of the chemical residue concluded that the airborne materials were not harmful and could easily be neutralized with soap and water.

The force of the explosion produced a crater four feet deep and approximately eighteen feet in diameter in the floor of the CSI plant, destroyed three twenty-five-foot-high exterior concrete walls, and partially destroyed the building’s concrete roof. Eleven buildings adjacent to the CSI Plant also sustained damage and a number of automobiles were damaged when the exterior wall of a building, which faced the CSI facility, collapsed onto the automobiles and crushed roofs, hoods and windshields.