BP has officially given up trying to seal its gushing oil well in the Gulf of Mexico until it can finish drilling at least one "relief well" in mid-August. Although its latest attempt to temporarily control the spill (by sawing off the damaged riser pipe and capping it to divert most of the oil to a ship on the ocean's surface) may succeed, what if the long-term "relief wells" solution fails, as experts say is entirely possible? (Watch an AP report about the most recent cleanup delay.) Here, a quick-guide to the worst-case scenarios:

What's BP saying?
In its original filing with the Interior Department, BP said it could handle a worst-case spill scenario of up to 162,000 barrels a day. BP CEO Tony Hayward recently lowered that figure to 60,000 barrels a day. The federal government says that 12,000 to 19,000 barrels a day are currently spilling into the Gulf.

What's the prognosis on the cut-and-cap effort?
Though the initial attempt failed when the diamond saw got stuck almost halfway through the 20-inch riser, BP technicians successfully sheared off the damaged pipe Thursday, albeit not as cleanly as hoped. If the cap can be affixed correctly, says oil consultant Nansen Saleri, BP might be able to suck up 90 percent of the gushing oil.

What happens in August?
The plan is to finish one or both in-progress relief wells, which would tap into the main well not far above the oil reservoir, relieving enough pressure on the gusher so BP can cement it shut. Among the things that could go wrong: The relief-well drilling might miss the main well, and the main well bore might be too damaged and leaky to plug.

What else could go wrong?
Hurricanes. The Atlantic hurricane season starts this week, and a big storm would at least temporarily derail relief efforts.

So, what if the relief wells fail?
If BP drillers just miss the main well, they can try again. In an undersea gusher off Australia last year, it took five attempts to connect with the main well, 10 weeks after the spill erupted. In this spill, "the worst-case scenario is Christmas time," says energy analyst Dan Pickering. "This process is teaching us to be skeptical of deadlines." At the current rate, 4 million barrels would spill into the Gulf by New Year's Day.

And what if BP just can't plug the well?
That's the ultimate worst-case scenario, says Fred Aminzadeh at the University of Southern California, and the well would probably continue to pour oil into the Gulf for more than a decade. The U.S. government on Wednesday officially shot down the idea of nuking the hole shut, and BP took conventional explosives off the table in May.

What happens to the Gulf during an endless spill?
It would be devastating for marine life, killing everything near the well and destroying all manner of life along hundreds of miles of coastline, according to Louisiana State University professor Harry Roberts. Months of gushing oil would also change the sea's chemistry, with unknown repercussions, says Woods Hole scientist Mak Saito. But nobody knows for sure. The Gulf apparently survived a 3.3 million–barrel spill off Mexico in 1979-80, and the biggest spill on record — the 8 million barrels dumped into the Persian Gulf during the first Iraq War — only did short-term damage to the shrimp, fish, and corals there, notes New York Times blogger Andrew Revkin. "Let’s hope the same holds true this time."

Sources: Bloomberg, New York Times (2), BusinessWeek, AP, NY Times Dot Earth (2)