The bleach being used to disinfect the streets of Leigu, to prevent the spread of disease after the earthquake, caught fire and injured up to 61 soldiers and an unknown number of civilians. From the Los Angeles Times:
A stockpile of chemicals being used to disinfect an earthquake-shattered town caught fire Thursday, injuring soldiers doing relief work, as heavy rain added to the misery of survivors in tents or lean-tos.
The official New China News Agency reported that more than 800 people were evacuated from the town of Leigu, in devastated Beichuan County, to avoid a cloud of chlorine gas caused by the blaze.
China Central TV showed soldiers extinguishing the blaze and several who were gasping for air being treated by medics.
It was not immediately clear why the bleach ignited, though substances in it can become explosive if heated or mixed with hydrocarbons such as those in diesel fuel.