BP knew it had "significant safety problems'' at its Texas City refinery and 34 other locations around the world well before last year's deadly explosion at the Texas plant, US investigators said in a damning report yesterday.

The US Chemical Safety Board also said cost-cutting helped compromise safety at the Texas refinery, BP's biggest, where a March 2005 blast killed 15 and injured 500 people in the worst US industrial accident in more than a decade.