1. Mississauga Train Wreck Presented to ES-317 at UWO in 1999. By Dick Hawrelak

2. The Incident Midnight, 10 Nov 79. 24 of 106 railcars derailed at Mavis Road. 11 propane cars. 3 toluene cars. 4 caustic cars. 1 - 90 ton chlorine car.

3. The Incident Cont’d Fire broke out almost immediately. Within 30 minutes, 3 of 4 propane cars BLEVEd. Sheets of steel were hurled 2,000 ft. Some property damage, no casualties. There was no apparent Cl2 release at this time.

4. What To Do? First responders decided to perform Cl2 dispersion studies in case Cl2 had not been released at this time. Called Dow Chemical for help. Worst Case Scenario - 180,000 lbs - instantaneous loss.

5. Results Of Dispersion

6. Decision Time ??? Decided to evacuate 217,000 people. Used TV, radio, street patrol, knocked on doors. Evacuation took 24 hours for total population. Majority returned after third day. All returned after sixth day.

7. Evacuation Data

8. The Failure It was determined that the derailment was caused by a journal bearing failure, or “Hot Box” on a toluene car. First responders had to withdraw to 1,500 ft. A brave photographer determined the Cl2 car was within 40 ft. of propane car. The Cl2 car had a major hole 2.5’ x 3’.

9. What happened to Cl2? 160,000 lbs of Cl2 was lost. Propane fires created extreme heat island. Cl2 drifted upward with heat intense heat rise or was consumed in the reaction. No one in Mississauga, at any time, ever smelled Cl2. For once, the Gods were with us this time!!