The sunken passenger ferry, MV Princess of the Stars, was carrying nearly 10,000 kilograms of the pesticide endosulfan. (Bullit Marquez/Associated Press)

Philippine officials suspended the retrieval Friday of hundreds of bodies believed trapped inside a sunken ferry due to fears divers may be exposed to toxic chemicals in the cargo hold.

Nearly 10,000 kilograms of the pesticide endosulfan intended for Del Monte's pineapple plantations went down with the ferry when it capsized in Saturday's typhoon in the central Philippines, vice-president Noli de Castro told reporters.

"Because this pesticide is dangerous, we have temporarily aborted the retrieval operations at the ship," he said.

More than 100 divers, including eight U.S. servicemen, had joined the search.

Undersecretary Maria Elena Bautista said ferry owner Sulpicio Lines violated maritime rules that prohibit carrying toxic or hazardous substances in passenger ships.

De Castro said the government is considering filing charges against Sulpicio.

Fish might be contaminated

The pesticide does not dissolve easily in water and could be lethal to humans, Health Secretary Francisco Duque said. He warned against eating fish caught in the area until tests show they have not been contaminated.

Norlito Gicana, executive director of the Fertilizer and Pesticide Authority, said four water samples have been taken from the ship and initial test results indicated no contamination of surrounding waters.

"With the results of the two samples obtained in the area, it appears negative — we have nothing to be worried about," he said. "We will still wait for the results of the two [other] samples."

It remained unclear how many of the 850-plus passengers and crew were trapped when the Princess of the Stars suddenly listed and then went belly up about 30 minutes after Typhoon Fengshen struck, leaving just the underside of the bow jutting from the water.

Only 56 survivors have been found, while 124 bodies have washed ashore or been recovered at sea, coast guard Cmdr. Danilo Avila said.

Divers in hazmat suits to examine chemical cargo

Coast guard chief Vice Adm. Wilfredo Tamayo said a salvage company was being consulted on possibly righting the seven-storey ship to speed up recovery work.

The pesticide was shipped in 206-kilogram boxes inside a steel container, Bautista said. A team of foreign divers with special chemical-resistant suits will examine the cargo and recommend how to haul it out of the ship, she said.

The government learned about the pesticide only after Del Monte informed the Fertilizer and Pesticide Authority about it, she said.

Typhoon Fengshen also left 505 people dead and 287 missing elsewhere in the country, the National Disaster Co-ordinating Council said.