It will be monitored to see if the cap can withstand pressure from oil and gas, starting Tuesday morning for six to 48 hours.

Work on the new capping operation began Saturday with the removal of a leaky cap that was capturing about half the flow of oil.

According to estimates, by Monday, the 83rd day of the disaster, between 89 million gallons and 176 million gallons of oil had poured into the Gulf, polluting the coastlines of US states.