WUHAN, Sept. 1-- A fire that killed five people in central China's Hubei Province was caused by human error and three people have been detained, investigators said Tuesday.

The fire, on the fourth floor of a five-story workshop at Tuochuang industrial park in Wuhan City, occurred around 4 p.m. on August 26. One person died at the scene, four more died later in hospital after jumping from the burning building in a bid to escape.

An investigation team was jointly organized by the provincial and city authorities. They concluded that the accident was due to illegal production activity.

According to investigators, workers were printing trademarks on gas bottles when gas leaked from the bottles and caused an explosion.

The three people detained include the person in charge of the chemical company that runs the workshop, the legal representative of the industrial park and vice general manager of the industrial park.