Witnesses described the scene at a Taiwan water park as "hell" after a ball of fire ripped through a crowd on Saturday, burning nearly 500 people, almost 200 of them seriously.

The blast was caused as colored powder being sprayed on the partygoers ignited.

Horrifying amateur video footage showed crowds of young revelers dancing in front of a stage and cheering as clouds of green and yellow powder covered them at the "color party".