Manila: One technician was killed and a chemical engineer remained in critical condition due to a toxic gas leak at the control room of a Petron oil refinery in central Luzon, police said on Monday.

Anthony Jed Reyes, a technician, and a chemical engineer whose name was not released were found unconscious at the control room of Petron early in the morning, Bataan police chief Manuel Gaerlan said.

Reyes died several hours after he and his co-worker were rushed to Joseph Hospital in Balanga, Bataan, said Gaerlan, adding the engineer has survived but is "not yet in a stable condition".