On June 3, 1989, two passenger trains passing each other between the Russian cities of Ufa and Asha ignited a hydrocarbon-air mixture from a leaking liquefied petroleum gas (LPG) pipeline. The resulting explosion killed at least 500 people, and injured hundreds more with serious burns.

Prior to the accident, engineers noticed a sudden drop in pressure at the pumping end of the LPG pipeline. Instead of investigating the trouble, the engineers responded by increasing the pumping rate in order to maintain the required pressure in the pipeline. The actual leakage point was about 890 miles downstream between the towns of Asha and Ufa, where the pipeline was located about a half mile from the Trans-Siberian Railway.

The escaping liquefied gas formed two large pockets in the low lying areas along the railway line. The gas cloud then drifted for a distance of 5 miles. Some hours later, after the main leakage had started, a train from Nizhnevartovsk destined for the Red Sea resort of Alder was approaching the leakage area when the driver noticed a fog in the area that had a strong odor. The driver of another train approaching from the opposite direction (Alder to Nizhnevartovsk) observed the same conditions as he approached the westbound train. Both trains were filled to capacity, with more than 1100 people on board, and as they approached the area, the turbulence caused by the trains mixed up LPG mist and vapor with the overlying air to form a flammable cloud. One of the trains ignited the cloud. Several explosions took place in quick succession followed by a ball of fire approximately 1 mile wide which raced down the railway track in both directions. Trees were flattened within a radius of 2.5 miles of the epicentre of the explosions and windows were broken as far away as 8 miles. The explosion thrust a pillar of fire into the nighttime skies that was visible to observers more than 60 miles away.

The accident resulted in 462 to 600 fatalities; the precise number is not known since many bodies were incinerated by the fireball. Most of the remaining pasengers were persons hospitalized, some due to 70-80% burn injuries. The victims included many children on their way to summer camps on the Black Sea.

Sources

• New York Times, Gas Blast and Uzbek Rioting Preoccupy Soviets, June 6, 1989
• New York Times, 500 on 2 Trains Reported Killed By Soviet Gas Pipeline Explosion, June 5, 1989.
• Robin, Mark L., Fire protection in telecommunication facilities, Process Safety Progress, volume 19, no. 2, pages 107-111 (2000).
• Time Magazine, Soviet Union Hard Lessons and Unhappy Citizens, Monday, June 19, 1989.