Enlarge By Chris Hawley, USA TODAY A piece of hardened oil sludge from a recent spill in Coatzacoalcos, Mexico. On Mexico's Gulf Coast, many residents who lived through the Ixtoc 1 blowout of 1979, the world's worst accidental oil spill, worry that the Deepwater Horizon spill could eventually reach their shores. COATZACOALCOS, Mexico  Here on Mexico's Gulf Coast, the Deepwater Horizon disaster has revived memories of the world's worst accidental oil spill, a 1979 blowout that spewed oil for nine months, devastated marine life and covered the Texas and Mexican coasts with gobs of crude. Now, people here are worried they may be in for a repeat of that disaster as ocean currents begin to catch oil from the Deepwater Horizon well and the Atlantic hurricane season gets underway June 1. There are strong parallels between the two spills. Like the Deepwater Horizon spill, the Ixtoc 1 spill on June 3, 1979, involved the failure of a blowout preventer device, a kind of emergency shutoff valve. In both cases, metal domes put over the well failed to stop the leaks. And in both cases, crews turned to something called relief wells dug horizontally through the seafloor to stop the spills, a technique that can take months. The Ixtoc I was an exploratory well being drilled in 160 feet of water about 60 miles northwest of Ciudad del Carmen on Mexico's Gulf coast. By comparison, the Deepwater Horizon well is 5,000 feet deep. The Ixtoc 1 well was owned by Petroleos Mexicanos, Mexico's state oil company, known as Pemex. But it was being drilled by Sedco, a predecessor to Transocean, owner of the Deepwater Horizon rig. At about 3 a.m. that 1979 day, the drill bit hit a high-pressure pocket of gas and oil. The drill pipe bent, the blowout preventer failed, and an oil geyser shot 150 feet before bursting into flames. OIL SPILL: Cleanup turns to untested tactic as efforts grow desperate PELICANS: Threatened by oil spill MAP: Oil slick growing in the Gulf GREEN HOUSE: Spill's impact on wildlife 'like a train wreck,' scientist says Armando Rodriguez was a deckhand on a ship that was laying pipe for the Ixtoc 1 well. He was standing watch when the drilling platform exploded, shooting a pillar of blue flame into the night sky. "The tower bent in half and went down in sparks," Rodríguez said. "We pulled out all the survivors. Then the oil started getting sucked into the engines, and the captain ordered us to back away." All 63 crewmembers were rescued without injury. In the April 20 Deepwater Horizon explosion, 11 died. The Ixtoc spill wiped out fishing along the Mexican coast for nearly two years, said fisherman Agapito Quintana Gomez, 73. Reaching under a boat behind the offices of the Miguel Aleman Fisherman's Cooperative in Coatzacoalcos, Quintana pulled out what looked like a lump of rubber: hardened sludge from a more recent oil spill. Inside, it was glossy black and smelled like especially pungent tar. "This stuff is poison," Quintana said. "It's going to go everywhere. We saw this happen in '79." Pemex and a series of U.S. contractors struggled for months to stop that leak. One company managed to close the well casing, but the oil broke through below the seal and caused another blowout. Another contractor built a dome for the well that it called the "Sombrero," Spanish for "hat," but oil continued to seep from cracks in the seafloor. In August 1979, balls of sticky tar began washing up on the hotel beaches of South Padre Island in Texas. Crews scraped them up with construction equipment and giant vacuum cleaners, and the Coast Guard stretched a net across the Port Mansfield inlet to catch submerged tar balls. Pemex began drilling two horizontal relief wells soon after the spill in June 1979, but they did not reach the Ixtoc 1 well until November, five months later. The crews used the relief wells to pump mud and steel balls into the gusher, finally capping the leak on March 25, 1980. BP, which owns the well in the Deepwater Horizon spill, began drilling its own relief wells on May 2 and May 16. They will take about three months to complete, the company says. Other techniques tried on the Ixtoc 1 might not work in the Deepwater Horizon spill. During the Ixtoc spill, scientists experimented with spreading fertilizer on the slick to encourage bacteria that break down the oil. That may not be a good idea near the Louisiana coast, which already has too much algae because of fertilizer runoff from the Mississippi River, said Terry Hazen, an oil spill cleanup expert at Lawrence Berkeley National Laboratory. The algae created a "dead zone" of low oxygen levels in the Gulf. The Ixtoc 1 leak spilled between 126 million and 210 million gallons of oil into the Gulf of Mexico, making it second only to the intentional oil spill of about 462 million gallons caused by retreating Iraqi troops in 1991 during the Gulf War, according to the Interior Department. After the 1979 spill, sea turtles and dolphins suffered. Scientists dug up hundreds of oil-covered turtle eggs and flew them to cleaner beaches to save them. Many residents now fear the BP spill will bring a repeat disaster. A variation in the Gulf currents that occurs every six to 11 months could eventually carry the oil toward Mexico, said Mike Pigott, a meteorologist with the AccuWeather forecasting firm. "The winds are dead out there now, but in June, they're going to start blowing again," said Roman Dominguez of the Gavilan del Rio Fisherman's cooperative in Coatzacoalcos. "That's what people are worried about. Everyone here remembers Ixtoc." 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