The Seattle Planning Commission warned city officials Friday that a new sports arena in Sodo could threaten port operations and industries that are vital to the economy and merit protection.

A new arena "holds a strong likelihood of displacing living-wage jobs and nearby businesses and disrupting container port operations and freight mobility," says a 17-page report by the commission, an advisory group of 16 volunteers appointed by the mayor and City Council.

More review and analysis should be conducted, the commission said, before the city takes further action on the proposal to build a $490 million arena with up to $200 million in public investment. "Our first suggestion is one of caution," the report said, referring to any approval of an agreement with private investors led by San Francisco businessman Chris Hansen.

Aides for Mayor Mike McGinn were quick to note the arena is an allowed use at the proposed location, something the commission report acknowledges.

McGinn's aides disagreed the arena would displace jobs and have a big impact on the Port of Seattle and trucking. Industrial zoning south of the proposed arena severely limits retail and office space, said Nathan Torgelson, city project manager for the Sodo arena.

The Sodo industrial area has faced pressure to convert its land to other uses, according to the commission, and the proposed arena likely would increase that pressure.

Industrial areas warrant some protection, the commission said, because they produce about 38 percent of the city's total business-and-occupation tax revenue annually.

Because an environmental-impact analysis has not been conducted yet, decision-makers lack sufficient information to identify and mitigate potential adverse impacts of the arena, the report said.

But Torgelson said transportation projects under construction or planned would alleviate traffic impacts caused by the arena.

A spokesman for Hansen said issues raised by the planning commission would be addressed by an economic-impact analysis proposed by King County Councilmember Bob Ferguson.

City Councilmember Tim Burgess, who is leading the council's review of the proposal, said the commission raised important questions.

"They're basically pointing to the cumulative impact of activities that pose a threat, if you will, to our maritime industrial jobs, and that is a very significant concern for the council," Burgess said.

Bob Young: 206-464-2174 or byoung@seattletimes.com