It seemed like a good idea at the time. In the early 1970s, a group of fishermen organized a campaign to dump 2 million used auto tires into the Atlantic Ocean, about a mile off the coast of Fort Lauderdale, Fla., between two living coral reefs. The goal was to build an artificial reef that would promote sea life. But it had the opposite effect: The mass of tires became an underwater blight. William Nuckols, with Coastal America, the federal office that is helping coordinate a cleanup of the tires, says the original goal was a good one. “The original intention,” Nuckols says, “was to try to provide a fish habitat and add to the natural coral reefs that were there.”