MANILA, Philippines (AP) — There is no indication that a big cargo of industrial fuel oil stored in a tanker that sank in stormy weather in Manila Bay has started to leak, the Philippine coast guard said Friday, and plans are being firmed up to try to siphon off the highly toxic shipment to prevent a major spill that could reach the bustling capital.

The tanker Terra Nova had left Bataan province en route to the central province of Iloilo with about 1.4 million liters (370,000 gallons) of industrial fuel oil stored in watertight tanks when it got lashed by huge waves and took on water. The crew struggled to steer the tanker back to port but it eventually sank shortly after midnight Thursday. The coast guard rescued 16 crewmembers but one drowned, coast guard spokesperson Rear Adm. Armando Balilo said.

“We’re racing against time to siphon off the oil to avoid an environmental catastrophe,” Balilo told reporters, adding that the plans could be hampered if the weather turns bad.