New Orleans ? Oil company engineers on Sunday finally succeeded in keeping some of the oil gushing from a blown well out of the Gulf of Mexico, hooking up a mile-long tube to funnel the crude into a tanker ship after more than three weeks of failures.

Millions of gallons of crude are already in the water, however, and researchers said the black ooze may have entered a major current that could carry it through the Florida Keys and around to the East Coast.

BP PLC engineers remotely guiding robot submersibles had worked since Friday to place the tube into a 21-inch pipe nearly a mile below the sea. After several setbacks, the contraption was hooked up successfully and funneling oil to a tanker ship. The oil giant said it will take days to figure out how much oil its contraption is sucking up.

The blown well has been leaking for more than three weeks, threatening sea life, commercial fishing and the coastal tourist industry from Louisiana to Florida. BP failed in several previous attempts to stop the leak, trying in vain to activate emergency valves and lowering a 100-ton container that got clogged with icy crystals.

A researcher told The Associated Press on Sunday that computer models show the oil may have already seeped into a powerful water stream known as the loop current, which could propel it into the Atlantic Ocean. A boat is being sent to collect samples and learn more.

Crews will slowly ramp up how much oil the tube collects over the next few days. They need to move slowly because they don’t want too much frigid seawater entering the pipe, which could combine with gases to form the same ice-like crystals that doomed the previous containment effort.

Two setbacks over the weekend illustrate how delicate the effort is. Early Sunday, hours before a steady connection was made, engineers were able to suck a small amount of oil to the tanker, but the tube was dislodged. The previous day, equipment used to insert the tube into the gushing pipe at the ocean floor had to be hauled to the surface for readjustment.