A vessel carrying roughly 370,000 gallons of industrial fuel oil capsized and sunk off of the Philippines on Thursday, causing an oil spill and killing one crew member. Officials now fear a “marine environment catastrophe,” saying they’re “preparing for the worst.”

The Philippine Coast Guard said the incident occurred just after 1 a.m. local time on Thursday about 3.6 nautical miles east of Lamao Point in the Philippines Bataan province. The motor tanker, called Terra Nova, was carrying 1.4 million liters, about 370,000 gallons, of industrial fuel oil when it capsized in rough seas. One person died and 16 other crew members were rescued. 

In their initial announcement, the coast guard said the oil spill had spread about 2 nautical miles due to a strong current. Coast Guard Admiral Ronnie Gil L Gava directed three response vessels to the spill site, saying they would administer oil dispersants to “immediately mitigate the impact” as officials prepared to siphon the area. 

“The PCG sets an operational target of seven days to finish siphoning the oil from the sunken tanker to stop further spread,” the Philippine Coast Guard said on Facebook. 

The sinking and oil spill occurred as the Philippines was hit by Typhoon Gaemi, which killed at least 34 people without even making a direct hit, officials said Friday, according to the Associated Press. The typhoon, which also had impacts in Taiwan and China, exacerbated the seasonal monsoon rains, causing rampant flooding and landslides. Some of those who died drowned or were electrocuted, the AP reported, while others, including a pregnant woman and three children, were buried in landslides. 

On Friday, Philippine Coast Guard Rear Admiral Balilo said officials “are still preparing for the worst-case scenario to address the potential negative impact to the marine environment” in regards to the oil spill, which officials said stems from the vessel’s fuel tank and not from cargo. 

“We are utilizing our manpower, mobilizing our resources, consulting with experts, and collaborating with LGUs and other stakeholders to avoid a marine environment catastrophe,” he said. 

The coast guard said the vessel did not go against regulations when it set out and that no storm signals had been issued at the time. According to CBS News partner BBC, Balilo said the captain had wanted to return to shore after realizing “the waves were really strong,” but that doing so proved difficult as they were sailing against them. 

Balilo said the spill could reach the Philippines capital of Manila – home to the country’s biggest port. 

“[It’s] the center of trade and economic activity,” Hernando Bacosa, an environmental sciences expert at the Mindanao State University, told the BBC. “This could possibly paralyze the capital and the neighboring areas.”

“They said the ship scooped up water until it eventually capsized,” he said, adding that crew members secured the vessel’s doors before jumping into the sea.