NEW ORLEANS (AFP)--Engineers have made "significant progress" in efforts to replace a cap over a gushing oil well in the Gulf of Mexico, Coast Guard Commander Thad Allen said Monday. "We've made significant progress. This could lead to the shutting of the well," Allen told NBC television's "Today Show" program. The development means that BP PLC (BP) may finally be on the verge of containing the worst environmental disaster in U.S. history, after weeks in which hundreds of thousands of barrels of crude have poured into the Gulf. Allen said he has asked BP to conduct a test on the well, possibly as early as later Monday, to determine how much pressure the cap can withstand. (END) Dow Jones Newswires July 12, 2010 07:49 ET (11:49 GMT)