Four missing in Czech factory blast

Four people are missing after a huge nitroglycerine explosion a factory in the Czech Republic.

The blast destroyed a building at the plant, which makes explosives for customers including the Czech military, and at least one person was injured, according to fire spokeswoman Vendula Horakova.

The explosion occurred at the Explosia AS plant in Pardubice, 60 miles east of Prague, the capital.

Harokova said the cause of the explosion was not immediately known and that rescue workers with sniffer dogs were searching the site.