JAKARTA, Indonesia (AP) — Waters off an Indonesian port city reek like a gas station after an oil spill and fire that killed four people over the weekend, an official said Wednesday.

Balikpapan city secretary Sayid Fadli said that the city on the island of Borneo was in its third day of a state of emergency following the weekend spill around Semayang Port.

"The city is in an emergency situation because of the oil spill and the bay is now like a gas station," Fadli said. "We have warned workers and residents around the bay to refrain from lighting cigarettes and make safety the priority."

Four people died after the fuel caught fire on Saturday, filling skies around the city with choking black smoke. One person is missing.

The city has distributed masks, and more than 1,300 people have suffered breathing problems, nausea and vomiting.

Fadli said police were still investigating the source of the spill, which as of Tuesday had an area of about 12 square kilometers (4.6 square miles). A preliminary investigation showed it was marine fuel oil.

The port authority was working with Chevron Indonesia and state-owned oil and gas company Pertamina, which operates an oil refinery in Balikpapan, in its attempts to clean up the spill, Fadli said.

Sanggam Marihot, head of the Balikpapan Port Authority, said five oil booms have been deployed and collected the equivalent of more than 14,600 barrels of oil.

Environment Minister Siti Nurbaya said in a statement that officials from the ministry were assessing the environmental damage.

The joint team responding to the emergency should prioritize residential areas for cleanup "due to the stench and other potential risks," she said.