TARRYTOWN, N.Y. (CBSNewYork) -- Millions of gallons of sewage are being dumped into the Hudson River on purpose and swimmers are being warned to stay out.
A 30-inch sewage pipe ruptured in Tarrytown -- north of the Tappan Zee Bridge and inside the now-dormant Croton Aqueduct -- and repair work is under way.
The rupture at the 40-year-old pipe on Wednesday afternoon required a partial system shutdown, which means raw sewage can't make it to the treatment plant in Yonkers, CBS 2's Lou Young reported.
Chlorinated sewage is now flowing into the Hudson both north and south of the break. The discharge began at 7:15 a.m. Thursday at Sleepy Hollow, officials said.
At the northern discharge point, the chlorine can clearly be smelled and the water looks unusually murky. Those signs and common sense are serving as a warning to stay out of the water.
As time goes by the geographic area affected will expand, officials said.
Heather McGill of the Westchester County Health Department warned boaters, swimmers and kayakers to avoid contact with the water and stay away until further notice.
"We're advising everyone from points south of Croton Point Park to avoid contact with the water," she told WCBS 880's Sean Adams.
WCBS 880's Sean Adams On The Story
For would-be swimmers, Thursday was torture.
"I'm going home now so I don't have to look at it -- because it's so tempting," said Irvington resident Dylan Harrison.
The health advisory runs from Croton down to Yonkers on both banks. On the Rockland side, the county's Health Department is advising people to avoid points south of Rockland Lake Park.
The advisory will remain in effect until at least Friday morning. New York City has yet to detect a problem, but is monitoring the situation.
1010 WINS' Steve Sandberg reports
The bottom line is that the sewage fix is underway, but it can't be quick.
"It normally runs at very high pressure, so if you put the concrete in there and you don't let it cure, it's going to blow out again and we're going to be back where we started," said Marian Pompa, of the Westchester Department of Environmental Protection.
Those comments indicate the problem may not be fixed until Saturday. It's unclear when people will be allowed back in the river.
So far, it is unclear what this could mean for Saturday's Ironman U.S. Championship, which includes a 2.4-mile swim in the Hudson, though that is over by Fort Lee, N.J.
It's one of the toughest endurance events in the world -- the swim, followed by a 112-mile bike ride, and ends with a 26.2-mile marathon, all in a single day.
But the 2,500 athletes might only be competing in two disciplines, if at all, CBS 2's Sean Hennessey reported Thursday night.
"You train for the unexpected, but this isn't something that you ever think is going to happen," first-time Ironman Sean McKenna said.
McKenna is one of the many who have trained countless hours and sacrificed time with his family to be able to say he finished an Ironman.
"To prepare for something for over 10 months and then two days before find out you're not going to do all three events is awful," he said.
Through no fault of their own, athletes may have their dreams deferred.
"It will be a disappointment that it wasn't a full Ironman race," said Andrew Motola, a first-time Ironman from Great Neck.
"You know you can't be a finisher of your first Ironman if you don't do the swim," added competitor Jennie Mann of Charlotte, N.C.
Race organizers told Hennessey this kind of problem is unprecedented. They're monitoring the Hudson's current and water quality and while they want to get the full event in as much as anyone they said it just may be too risky.
"We have to keep people safe first and, ultimately, going home to their families is more important than any athletic endeavor," said Shane Facteau of Ironman America.
FDNY para-athlete Dave Kreysman said he is rolling with whatever comes his way.
"Races change on a daily basis. It's the nature of the beast. Nothing is guaranteed," he said.
Others said that without the swim, whoever actually wins will have a victory with what amounts to an asterisk next to it.
"For me, it changes the whole race. You prepare all year round to do a full Ironman and to spend all the money and effort," said Carmel Zahran of Chicago.
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