The demolition of the Bay Bridge’s old eastern span — postponed last week — is scheduled to kick off early today, starting with the removal of the upper deck roadway between the cantilever section’s two iconic peaks.

Originally scheduled for last Wednesday, the dismantling was put on hold the night before after contractors indicated the debris containment system was not completely in place.

Crews won’t be cutting any steel from the cantilever, which contains toxic lead paint, until early next year. But the project’s first phase — prying up the 1,400 feet of upper roadway motorists used to travel toward San Francisco — also requires precautions, said Bay Bridge spokesman Andrew Gordon.

“Anything might fall from the upper deck. It could be a piece of concrete, could be a piece of rebar,” Gordon said. “They want to have as little debris dropping down so it’s easier to haul the upper deck out. And on the bottom deck, there are vehicles moving back and forth.”

Demolition preparation work began immediately after the new span opened Labor Day weekend. The removal of 1,400 feet of the approximately 2,400-foot-long cantilever is expected to take six weeks.

“They’ll be using jackhammers and saws, so it’ll be noisy,” Gordon said. “It won’t be any noisier or less noisy than when people were driving on the original span and work was going on on the new span. But this work will probably be heard more than seen.”

The entire demolition is projected to take three years. The second contract will be awarded mid-2014 for the portion east of the cantilever, and the third contract for the underwater infrastructure will follow later next year.