Mariner Energy shares fall after platform explodes

Shares of Mariner Energy tumbled Thursday after an explosion in one of the company's production platforms in the Gulf of Mexico.

The explosion, on Mariner's Vermilion Oil platform 380, took place at least 80 miles south of Vermilion Bay on the Louisiana coast, according to John Edwards, chief petty officer of the U.S. Coast Guard in New Orleans.

7digg Mariner Energy said that all 13 members of the crew were evacuated safely from the fire. There were no injuries and no evidence of a spill, the company said.

"The cause is not known and an investigation will be undertaken," said the company, in a press release.

Shares of Mariner Energy (ME) fell more than 4%, partially recovering from its initial plunge of 5%.

The Coast Guard said the platform is in 340 feet of water. The workers started emergency shut down procedures before abandoning the platform, which does not have a blowout preventer, according to the Coast Guard.

The Coast Guard initially said that the platform was in production at the time of the accident, but then retracted that statement due to conflicting information.

A faulty blowout preventer has been blamed for the devastating spill from the BP (BP)-controlled platform that killed 11 workers in April, also in the Gulf of Mexico.

Neal Dingmann, analyst for Wunderlich Securities, said that the occurrence of two high-profile platform accidents within a few months of each other is rare. The likely outcome will be a more tightly regulated industry.

"Although this incident is very different from Macondo [the well operated by BP,] I think the government will continue to look at this and will add more rules and regulations," he said.

In April, Mariner Energy announced that it had formed a merger with another oil exploration company, Apache Corp. (APA, Fortune 500) The stock price for Apache slipped more than 1% in afternoon trading.

Mariner Energy would still be considered the operator of the platform because the merger isn't scheduled to be completed for several weeks, according to Apache spokesman Bob Dye.

A production platform is built after the drilling of an oil or gas well. The platform often remains in operation for years, pumping pressure down the hole to keep the well flowing.

Nicholas Pope, an analyst for the investment bank Dahlman Rose, said the Mariner Energy platform is in the Gulf Shelf, which is not a deepwater area so it would not be affected by the ban on deepwater drilling.

CNN's Tim Lister contributed to this story.