Updated at 8:27 p.m. EDT
Tar balls from the Gulf oil spill found on a Texas beach were confirmed Monday as the first evidence that gushing crude from the Deepwater Horizon well has reached all the Gulf states.
BP says the tar balls were probably brought in on hulls of ships that came through oily water in the Gulf, reports CBS News correspondent Mark Strassmann.
A Coast Guard official also said it was possible that the oil hitched a ride on a ship and was not carried naturally by currents to the barrier islands of the eastern Texas coast, but there was no way to know for sure.
The amount discovered is tiny in comparison to what has coated beaches so far in the hardest-hit parts of the Gulf coast in Louisiana, Mississippi, Alabama and the Florida Panhandle. It still provoked the quick dispatch of cleaning crews and a vow that BP will pay for the trouble.
"Any Texas shores impacted by the Deepwater spill will be cleaned up quickly and BP will be picking up the tab," Texas Land Commissoner Jerry Patterson said in a news release.
The oil's arrival in Texas was predicted Friday by an analysis from the National Oceanic and Atmospheric Administration, which gave a 40 percent chance of crude reaching the area.
"It was just a matter of time that some of the oil would find its way to Texas," said Hans Graber, a marine physicist at the University of Miami and co-director of the Center for Southeastern Tropical Advanced Remote Sensing.
About five gallons of tar balls were found Saturday on the Bolivar Peninsula, northeast of Galveston, said Capt. Marcus Woodring, the Coast Guard commander for the Houston/Galveston sector. Two gallons were found Sunday on the peninsula and Galveston Island, though tests have not yet confirmed its origin.
Woodring said the consistency of the tar balls indicates it's possible they could have been spread to Texas water by ships that have worked out in the spill. But there's no way to confirm the way they got there.
The largest tar balls found Saturday were the size of ping-pong balls, while the ones found Sunday were the size of nickels and dimes.
Galveston Mayor Joe Jaworski said he believed the tar balls were a fluke, rather than a sign of what's to come.
"This is good news," he said. "The water looks good. We're cautiously optimistic this is an anomaly."
The distance between the western reach of the tar balls in Texas and the most eastern reports of oil in Florida is about 550 miles. Oil was first spotted on land near the mouth of the Mississippi River on April 29.
The spill is reaching deeper into Louisiana. Strings of oil were seen Monday in the Rigolets, one of two waterways that connect the Gulf with Lake Pontchartrain, the large lake north of New Orleans.
"So far it's scattered stuff showing up, mostly tar balls," said Louisiana Office of Fisheries Assistant Secretary Randy Pausina. "It will pull out with the tide, and then show back up."
Pausina said he expected the oil to clear the passes and move directly into the lake, taking a backdoor route to New Orleans.
The news of the spill's reach comes at a time that most of the offshore skimming operations in the Gulf have been halted by choppy seas and high winds. A tropical system that had been lingering off Louisiana flared up Monday afternoon, bringing heavy rain and winds.
Forecasters at the National Hurricane Center said there was a 60 percent of the storm becoming a tropical cyclone.
Last week, the faraway Hurricane Alex idled the skimming fleet off Alabama, Florida and Mississippi with choppy seas and stiff winds. Now they're stymied by a succession of smaller storms that could last well into this week.
Officials have plans for the worst-case scenario: a hurricane barreling up the Gulf toward the spill site. But the less-dramatic weather conditions have been met with a more makeshift response.
Skimming operations across the Gulf have scooped up about 23.5 million gallons of oil-fouled water so far, but officials say it's impossible to know how much crude could have been skimmed in good weather because of the fluctuating number of vessels and other variables.
The British company has now seen its costs from the spill reach $3.12 billion, a figure that doesn't include a $20 billion fund for damages the company created last month.
The storms have not affected drilling work on a relief well that BP says is the best chance for finally plugging the leak. The company expects drilling to be finished by mid-August.
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Alex Downgraded, but Hampering Gulf Cleanup