A tanker carrying 1.4 million litres of industrial fuel oil has sunk in Manila Bay following a maritime incident.
One person is missing, 16 of the 17 crew members have been rescued.
Four crew members are receiving emergency medical care, ABS-CBN News reports.
The MT Terra Nova sank in Manila Bay, nearly seven kilometers from the municipality of Limay.
The Philippine Coast Guard is conducting a search and rescue operation to find the missing crew member.
Rescuers managed to locate and bring ashore 16 of the 17 crew members. One person remains missing.
The ship was heading to Iloilo but sank in Manila Bay near the capital early in the morning.
MT Terra Nova capsized and eventually sank due to heavy rains and the seasonal monsoon.
The Coast Guard said it was investigating the marine incident, but strong winds and high waves were making clean-up efforts difficult.
The oil slick, about 3.7 km long, was carried in different directions by a strong current. Marine conservationists were mobilized to contain it.
Thousands of fishermen have been ordered to stay on shore until it is safe to fish.