A fire in an old munitions depot near the Bulgarian capital Sofia triggered a series of explosions Thursday, but, though the crackling of ammunition continued into the afternoon, the worst was over, Defence Minister Nikolay Tsonev said.
The greatest threat in the accident at the depot in the suburb of Chelopechene had been from some 20 tons of the highly explosive trinitrotoluol (TNT) , reportd dpa.
The stored TNT had only burned, without exploding, Tsonev said, stressing also that there was no threat of air pollution, particularly as the wind blew the smoke away from the city.
The defence ministry released a detailed list of what was stored in the depot - infantry and artillery ammunition, bombs, grenades, detonators, explosives and "other pyrotechnical means."
The ordnance was mostly from the Soviet era, brought for de-commissioning to the facility which has been in use since 1918. The blast was presumably caused by inadequate storage.
The loudest detonations, heard in Sofia, occurred in the early morning, shortly after the fire broke out. No major injuries were reported - only a couple of people with cuts from flying shards of glass - in spite of the power of the blasts, civil defence said.
The closure of Sofia international airport, also east of the city, safety reasons was extended beyond the initial target of 2:00 pm (1100 GMT). Windows had been shattered at the facility, but apparently no further damage was reported. Some ordnance was, however, found on the grounds.
Planes arriving from abroad were redirected to Plovdiv, 150 kilometres to the east.
A slight earthquake, of 3.2 on the Richter scale, sent some in Sofia into panic Thursday afternoon. The quake was unrelated to the blast, local experts stressed.
Some 1,700 people living within three kilometres of the depot were evacuated amid concerns that more blasts could damage their homes or infest the area with dangerous unexploded ordnance.
Emergencies Minister Emel Etem said the damage was largely limited to shattered windowpanes and cracks in walls, but appealed to local authorities in Sofia to secure shelter for those who would likely be forced to spend the night away from their homes.
Bulgaria was a member of the Communist Warsaw Pact until it collapsed in 1990. The Balkan nation joined NATO in 2004, but is yet to deal with up to 100,000 tons of unusable, but potentially deadly leftover ordnance.
The accident Thursday, the first of the sort since Bulgaria joined NATO, was presumably triggered by lax safety procedures.
At least 25 people were killed and 300 injured in a blast during a botched cleanup of a decades-old munitions depot in March in Albania, which was invited to join NATO a month later.
Albania is required to decommission its rotting ordnance from hundreds of depots the harsh Communist regime had sown nationwide in the five decades before its collapse in the 1990s.