With crucial votes looming on the Southwest Corridor light rail project, opponents Wednesday night warned of the potential risk of a freight train spilling hazardous material along the transit route.

At a hearing held by Hennepin County and the Metropolitan Council, Mary Pattock, who lives a few blocks from the future light-rail route, raised the specter of a freight accident involving "highly flammable ethanol" a few feet from electrical wires of the transit line in the Kenilworth corridor.

Bob Carney, a frequent candidate for local office, warned of an ethanol accident affecting a light-rail tunnel.

But a representative of the North Star Chapter of the Sierra Club called the Southwest plan — including the tunnel — part of a "truly great 21st-century transportation network."

"We urge Hennepin County and the Metropolitan Council to approve … the single tunnel solution," said Alex Tsatsoulis, who deals with land use and transportation issues for the Sierra Club.

About 100 people attended the hearing in Minneapolis, with support and opposition split.

The Met Council, the agency overseeing the project, voted last month in favor of a Southwest plan that includes a light-rail tunnel running south of the channel between Lake of the Isles and Cedar Lake in Minneapolis. The light rail would surface to cross the channel and continue north in the Kenilworth corridor.

Hennepin County is set to vote on the project Tuesday; Minneapolis votes on Aug. 29.

Concerns linger about the line's potential impact on the Kenilworth corridor. The proximity of the future light-rail line to existing freight tracks was raised by a group of residents last month in a letter urging the Federal Transit Administration to withhold funding until more environmental studies are completed. Attorney Tom Johnson cited concerns about ethanol now being transported by freight in the corridor.