SAN FRANCISCO -- The legal wrangling continues over Walmart's plans to expand its Antioch store into the East Bay's first supercenter.

The California Healthy Communities Network, a coalition of environmental, civil rights and labor groups, filed a petition with the state Supreme Court last week, challenging a recent appellate court decision affirming Antioch City Council's September 2010 application of its development plan when it approved the retailer's expansion without looking at environmental issues.

"There are still significant questions left unanswered. There is an interpretation of law that needs to be clarified," said Phil Tucker, project director for the Healthy Communities Network.

In a 31-page filing, the Healthy Communities Network asked the court to consider whether an appellate court decision involving a San Diego redevelopment project means agencies don't have to consider full environmental studies when looking at design review applications. The Jan. 4 petition also asks if a city can interpret land use laws in a manner that conflicts with its own historic interpretation to avoid full environmental review.

"We're asking the court to look at how the San Diego case was applied. We feel it was used inappropriately in Antioch, but it has more far-reaching implications as far as the interpretation of its use, " Tucker said. "It's worth a shot."

The court has 100 days to review and respond to the petition either by accepting it for review or dismissing it.

Walmart first approached Antioch in 2004 -- four years after its store opened -- about expanding the 141,500-square-foot store in Williamson Ranch Plaza.

In both 2007 and 2010, Antioch required Walmart to review the environmental effects of building the supercenter, twice rejecting its environmental documents in split decisions. In July 2010, a majority of the council said the study underestimated potential urban decay, or economic and environmental effects, in the area.

Antioch's council reversed its decision a month later after legal counsel for Walmart and the city argued that it could not consider environmental issues in a design review application, citing the San Diego case, and said that Walmart's expansion was allowed in the original approval for Williamson Ranch Plaza in 1998.

A Contra Costa Superior judge disagreed in fall 2011, saying that Antioch had required environmental studies in the past and could not change its interpretation of its laws. The 1st District Court of Appeal reversed that ruling in November.

City Attorney Lynn Tracy Nerland reiterated this week that the appellate court found Antioch's actions to be "legal and appropriate" and it will "wait to see" if the decision is reviewed.

Walmart officials say they are pleased with the appellate court decision, and are reviewing its legal options in regards to the latest matter. The company remains committed to the 33,575-square-foot expansion, which would bring 85 new jobs, said Rachel Wall, a Walmart spokeswoman.

"We believe Antioch residents will benefit from the jobs and affordable groceries coming to their neighborhood," Wall said.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.

TIMELINE
Last week's court filing is the latest development in Walmart's years-long effort to expand its Antioch store into the East Bay's first supercenter.
Here is a timeline:
January 2000 -- Walmart opens 134,000-square-foot store at Lone Tree Way and Hillcrest Avenue.
June 2004 -- Walmart announces intention to expand store by 72,980 square feet and turn it into a 24-hour supercenter. City says it must study traffic and noise effects.
Sept. 20, 2006 -- Planning Commission approves environmental study; appeal is filed.
October 2006 -- City Council hears arguments for and against expansion and delays decision.
February 2007 -- City Council rejects Walmart's plans for 64,980-square-foot expansion.
January 2010 -- Walmart submits new plans to Antioch, calling for 33,575-square-foot expansion and no 24-hour operations; city says it must study environmental effects.
May 2010 -- Planning Commission approves Walmart expansion plans; decision is appealed to City Council.
July 2010 -- City Council rejects Walmart expansion, citing economic concerns.
August 2010 -- Proposal brought back to council after city legal counsel determines that environmental review is not needed for expansion.
Sept. 28, 2010 -- City Council approves Walmart expansion.
October 2010 -- Walmart opponents file lawsuit over city's decision.
Oct. 13, 2011 -- Contra Costa Superior Court sides with Walmart opponents, effectively reversing city's decision.
January 2012 -- Walmart files appeal with state Court of Appeal.
Nov. 27, 2012 -- Appellate court reverses Contra Costa Superior Court ruling, allowing Walmart expansion to proceed.
January 2013 -- Walmart opponents file petition for review with California Supreme Court.