out from $360 million to $650 million for damage or loss of the sinking Petrobras oil rig in Brazil, insurance market sources said Friday.

The 40-story oil platform, the world's largest, was rocked by three explosions on Thursday which killed one and left nine missing.

The rig is currently tilting and may sink within 48 hours, owner Petrobras, the Brazilian oil giant, told reporters.

Damage to the rig so far totaled about $360 million, a US spokesman for reinsurer Swiss Re told Reuters. If the rig is totally lost, that could rise to $650 million, said Merrill Lynch insurance analyst Jay Cohen.

That is only a fraction of the world's most expensive man-made disaster, the 1988 Piper-Alpha oil rig explosion off the British coast, which killed 167 and cost insurers $2.9 billion, adjusted for inflation.

"We understand that the Petrobras rig carried coverage of $500 million, plus an excess layer of $150 million for total coverage of $650 million,'' said Cohen in a research note.

Cohen said 16 insurers covered the $500 million layer of insurance between them, a practice common in the insurance industry, where big risks are shared out to avoid any one company taking a massive loss.

Only three of those unidentified companies covered more than 10 percent of the risk, Cohen said.

"Each of these companies will likely have reinsurance for this event and we believe much of this reinsurance will be in the Lloyds and London market,'' said Cohen, referring to the Lloyds of London insurance market, which consists of groups of underwriting syndicates that act like mini-insurance companies, spreading risks among themselves.

Cohen said companies that were likely to have some exposure to claims included Bermuda-based ACE Ltd. and XL Capital Ltd., which both own operations at Lloyds. Both those companies declined to comment on possible losses from the accident.