Almost a year after the massive BP oil disaster began with the explosion of the Deepwater Horizon oil rig, sticky clumps of oil are once again washing up on Louisiana beaches. Fishermen say the slick is several miles long. What caused the latest spill, and how much damage will it do? Here, a brief guide:

How bad is the spill?

Photographed from the air, the slick appears to stretch for miles. Oil has washed up in spots along 30 miles of coastline around Grand Isle, one of areas hit hardest by last year's spill, the worst offshore oil disaster in history. But this time, the amount of oil in the Gulf appears to be limited. It's "nowhere near the volume of Deepwater Horizon," says Coast Guard Rear Adm. Mary Landry, as quoted in The Wall Street Journal, "but still significant enough."

What caused it?

State agents traced the oil to a Houston company — Anglo-Suisse Offshore Partners. Anglo-Suisse has accepted responsibility, saying it had a small leak in a dormant well about 30 miles southeast of Grand Isle. It has been out of production since Hurricane Katrina, which damaged the platform.

Will it wreak much environmental damage?

Probably not; we're unlikely to see oil-soaked birds this time around. Anglo-Suisse announced Tuesday night that it had plugged the well for good, so the environmental damage should be limited.

Still, the timing couldn't be worse for Big Oil, could it?

No, especially when the oil and gas industry is trying to convince regulators, politicians, and the public to let it recommence deep-water drilling in the Gulf of Mexico, its goal now that new regulations are in place to prevent a repeat of BP's disaster. And if Anglo-Suisse is found to have underreported the size of its spill to avoid government oversight (as some commentators suspect), it could face stiff fines. Also, says Brett Michael Dykes at Yahoo!, now that the company is on record as the responsible party, "it will be on the hook for the full cleanup expenses."

Sources: Business Insider, Wall St. Journal, Times-Picayune, TIME, Yahoo!