BP appeared Monday night to have placed a new containment cap on its crippled well in the Gulf of Mexico that’s been gushing oil since an explosion and fire April 20.

The company hopes the new cap will be able to completely contain the leaking oil, but tests are still needed to determine its effectiveness.

Video supplied by BP showed robotic arms gingerly lowering the new cap over the well, with little oil appearing to escape.

If the new cap does not completely contain oil from the crippled well, some may have to be brought to the surface to waiting containment ships. But under a worst-case scenario, there could be new damage to blowout preventer.

The tests are due to begin Tuesday morning, CNN’s reported on “The Situation Room.” The process could take anywhere from six hours to two days.

Retired Coast Guard Adm. Thad Allen, the man in charge of the federal response, said Monday scientists will be checking the pressure inside the well, and then determining whether the cap is holding the oil in or if crews will need to continue siphoning oil.

A critical step is making sure there’s no hydrate buildup, according to BP Chief Operating Officer Doug Suttles.

In the best-case scenario, the containment cap would have the ability to close down the valves and slowly contain all the oil, Allen said.

(Source: CNN)