Plans to create a downtown area in Carson with dense housing and commercial centers near City Hall were quietly pushed through this week by the City Council.

The council Tuesday unanimously approved the sale of two properties to Carson Residential Communities, a developer that plans to build the largest market-rate housing and commercial project in years.

Little has been said publicly about the development, which calls for more than 350 homes and 32,000 square feet of commercial space on a 5.5-acre lot at the northwest corner of Carson Street and Avalon Boulevard. The other corners of that intersection are now occupied by City Hall and a relatively new collection of luxury condominiums, senior apartments and restaurants called City Center.

Adding dense housing to an area previously zoned for commercial uses will tax the city’s infrastructure, though major street improvements are planned, officials said.

The Carson Street Master Plan, which is scheduled for a vote at the March 4 council meeting, calls for nearly $19 million in upgrades to Carson Street between the 405 and 110 freeways. It has been in the works for more than a decade and will bring new turn lanes, street furniture, bike lanes, wider sidewalks, public art, streetlights and more.

The Carson sheriff’s station also is planning to expand its facilities in 2017, officials said.

On Tuesday, the council voted to sell two city lots that will be used to create the new mixed-use development. The city sold 615 E. Carson St. for $2.7 million and 21521 Avalon Blvd. for $1 million to Carson Residential Communities.

The council also moved forward with long-discussed plans to annex Rancho Dominguez, a 2.6-square-mile unincorporated county area adjacent to Carson’s northeast border. Four years ago, it seemed to be too costly a prospect for Carson. But a new consultant studied the issue and found that the city could make money if it brought the area within its boundaries.

Allan D. Kotin & Associates of Los Angeles found the city of Carson could net more than $2 million a year if Rancho Dominguez is annexed, though that figure changes along with economic conditions. Council members were heartened by the new figures and Mayor Jim Dear asked that the annexation application — typically a lengthy one — be a priority.

Total property values in largely industrial Rancho Dominguez are $1.67 billion and the area has 2,700 residents and 15,100 employees, Dear said.

“This is the third attempt we’re making in more recent times,” the mayor said. “We’re trying to get to a tax-sharing agreement with the county. We’re moving forward as quickly as we can.”

Also on Tuesday, the council approved a new city plan to rehabilitate properties that have been contaminated by hazardous chemicals left from various landfills, auto salvage yard, oil refineries, electronics manufacturing and other uses common in Carson from the 1940s to 1960s.

The Carson Reclamation Authority, as it is called, would allow officials to issue bonds and find other funding sources to clean properties while limiting the city’s liability. The authority will be something of a replacement for the Redevelopment Agency, which provided the city with a funding mechanism to improve blighted areas before the state dissolved all redevelopment agencies.

“I want to commend the staff for coming up with this creative solution,” Councilman Albert Robles said, just before the council voted 4-0 in favor.