A second, smaller oil containment box was lowered into the sea near the blown-out well in the Gulf of Mexico, but it won't be placed over the spewing well right away.

BP spokesman Bill Salvin says company engineers want to make sure everything is configured correctly to avoid the same buildup of ice crystals that stymied their first attempt at using a larger box that was about 100 tons.

This box will be connected to a ship on the surface by a pipe-within-a-pipe when it's lowered. Crews plan to pump in heated water and methanol so ice won't build up.