NEW ORLEANS -- The eruption of a fire on an oil platform in the Gulf of Mexico - which left two workers missing and four others badly burned - is a vivid reminder of the dangers involved in offshore drilling and the risk it poses to the Gulf's ecosystem and shoreline.

The Coast Guard was searching Saturday for two workers missing after the fire broke out Friday, sending an ominous black plume of smoke into the air reminiscent of the 2010 Deepwater Horizon explosion that transformed the oil industry and life along the Gulf Coast.

The blaze, which started while workers were using a torch to cut an oil line, critically injured at least four workers. Those workers were burned, but their burns were not as extensive as initially reported, said Leslie Hoffman, a spokeswoman for Black Elk Energy, which owned the platform. Their conditions Saturday were stable but critical, she said.

Coast Guard officials said in a news release Saturday that helicopters were searching for the missing workers from the air, while a cutter searched the sea.

The images Friday were eerily similar to the Deepwater Horizon blaze that killed 11 workers and led to an oil spill that took months to bring under control. The fire came a day after BP PLC agreed to plead guilty to a raft of charges in the 2010 spill and pay a record $4.5 billion in penalties.

There were a few important differences between this latest blaze and the blaze that touched off the worst offshore spill in U.S. history: Friday's fire at an oil platform about 25 miles southeast of Grand Isle, La., was put out within hours, while the Deepwater Horizon burned for more than a day, collapsed and sank.

The site of Friday's blaze is a production platform in shallow water, rather than an exploratory drilling rig looking for new oil on the seafloor almost a mile deep.

The depth of the well blow-out - a mile below the surface - proved to be a major challenge in bringing the disaster under control.

The Black Elk platform is in 56 feet of water - a depth much easier for engineers to manage if a spill had happened.

A sheen of oil about a half-mile long and 200 yards wide was reported on the Gulf surface, but officials believe it came from residual oil on the platform.

"It's not going to be an uncontrolled discharge from everything we're getting right now," Coast Guard Capt. Ed Cubanski said.

Hoffman, the Black Elk Energy spokeswoman, said Saturday that there were still no signs of any leak or spill at the platform site.

BP's blown-out well spewed millions of gallons of oil into the sea, about 50 miles southeast of the mouth of the Mississippi River on the east side of the river delta. The crude fouled beaches, marshes and rich seafood grounds.

After Friday's blaze, 11 people were taken by helicopter to area hospitals or for treatment on shore by emergency medical workers.

The production platform owned by Houston-based Black Elk Energy is on the western side of the Mississippi River delta. The Coast Guard said 24 people were aboard the platform at the time of the fire.

Cubanski said the platform appeared to be structurally sound. He said only about 28 gallons of oil were in the broken line on the platform.

David Smith, a spokesman for the Interior Department's Bureau of Safety and Environmental Enforcement in Washington, said an environmental enforcement team was dispatched from a Gulf Coast base by helicopter soon after the Coast Guard was notified of the emergency. Smith said the team would scan for any evidence of oil spilling and investigate the cause of the explosion.

Black Elk is an independent oil and gas company. The company's website says it holds interests in properties in Texas and Louisiana waters, including 854 wells on 155 platforms.

John Hoffman, Black Elk's president and CEO, said in an email early Saturday morning that he was leaving Houston for Louisiana to assist in the investigation and help the families of the missing and injured workers.

"My entire focus is the families and workers. Nothing else matters at this point," he wrote.