Police say five people were killed early Monday in an explosion at an illegal fireworks factory in southern China.

Police in Guizhou province are investigating the cause of the blast which ripped through the factory in the village of Lanjiang. One other person was injured.

China has shut down thousands of illegal fireworks workshops to try to end accidents caused by dangerous production conditions or shoddy safety equipment. However, the industry remains an economic lifeline for many poor rural regions, providing an incentive to avoid regulators.

Fireworks are used in China to celebrate auspicious occasions such as weddings and the opening of new businesses, as well as in rituals for the dead.

Monday's explosion came on the next-to-last day of the weeklong National Day holiday, when many offices are closed and police resources are redirected to ensure transportation safety and crowd control at scenic sights that are mobbed by domestic tourists.