Explosion at Czech ammunition plant disrupts shell production
The explosion at the Czech ammunition factory in Polička has been contained, and shell production has resumed. Here is what is known about the incident at the plant, which manufactures weapons, among others, for the needs of the Ukrainian army.
On Tuesday, 25 March, an explosion occurred at the Czech ammunition factory in Polička, resulting in one person being seriously injured and subsequently transported to a hospital in Olomouc and according to a statement from STV GROUP, a machine for melting TNT exploded, most likely due to a technical malfunction.
The fire did not spread to nearby buildings, but production was halted, and approximately 740 people in the building and nearly 90 people from adjacent buildings were evacuated.
A commission and the police in the Czech Republic are investigating the cause of the fire. STV GROUP's management is cooperating with all services to clarify the incident. As of 26 March, ammunition production was resumed on other production lines.
Artillery shell production — a dangerous process
The most popular and frequently used artillery shells during the war in Ukraine are classic artillery shells with a truncated rear. Also standard is the variant with a base bleed unit, which increases the range by 30% by reducing the drag at the base of the shells.
These shells are essentially cast-iron or steel casings with a thread on the tip, into which melted TNT or another explosive material such as Composition B (a mix of TNT and RDX) is poured. For this purpose, it must be heated to an appropriate temperature, which is about 80 degrees Celsius for TNT. The process must be closely monitored because exceeding the temperature by several tens of degrees can lead to self-ignition and explosion.
After cooling, these shells are painted. Then, manufacturer markings are applied, and caps are added to protect the thread for installing the fuze. This fuze can be a simple impact solution, a more advanced one allowing for airburst or an M1156A1 PGK module turning an unguided shell into a cheap version of the Excalibur.
Here’s what the Czechs produce
The Czech company STV GROUP specialises in shell production. Their " portfolio " includes 81 mm mortar shells, post-Soviet 122 mm and 152 mm artillery shells, and NATO calibre 155 mm. The accident likely occurred on an old production line, which has been operating at maximum efficiency since 2022.
It can be assumed that the recently opened line for 155 mm shells remains intact. Among other things, Czechs produce a licensed variant of the M107 shell there, containing approximately 6.6 kilograms of TNT and providing a range of 22.5 kilometres and 30.5 kilometres for artillery systems with barrels of 39 calibres (M109) or 52 calibres (DITA or Krab).
Additionally, the Czechs produce newer shells marked as ER-HB with a base bleed unit extending the range up to 40 kilometres for longer barrels. They contain roughly 9 to 10 kilograms of TNT or other explosive material. The annual production of Czech STV GROUP plants was expected to reach a volume of 200,000 shells by the end of 2025 and 300,000 by the end of 2026, but ultimately, these numbers may be lower due to the accident.
