. good evening. that delicate operation to place a new cap atop the gushing oil well beneath the gulf of mexico got under way this afternoon. it s a gambit for the time being means there is no cap over the leak. that means thousands of barrels of oil freely pour into the sea. bp says the trade-off is by as soon as next week engineers could have a new tighter-fitting cap in place. one capable of capturing most, if not all the leaking oil. it s an operation fraught with risks and outlined with plenty of caveats, but it is raising a glimmer of hope tonight amid what had been a blackened tide of mostly bad news. anne thompson is in venice, louisiana, with the greatest for us. good evening. reporter: good evening, lester. there is a whole lot of hope riding on that work going on at the leak side tonight. an ironic and disheartening twist for the people of louisiana, bp says to do a better job of containing the oil, it must first let more oil, in fact a lot more oil flow out.