36 tons of steel from what was once the Bay Bridge's eastern span will reappear on Treasure Island next month, in the form of an interactive art piece.

On September 22, "Signal," a 25-foot steel ring by San Francisco-based conceptual artist Tom Loughlin, will be installed on the western edge of Treasure Island, near the restaurant Mersea. The piece is constructed from what was once three girders of the bridge, with an original signal light from its top.

There will also be a sound component calibrated to mimic a foghorn, which Loughlin sees as a "comforting sound, but also a warning of danger." Viewers will also be able to step into the ring, to experience soft pulses of light.

At work on welding the installation.

Five years ago, the Oakland Museum of California partnered with the Toll Bridge Program Oversight Committee to set up a Bay Bridge Steel program. 15 artists, architects, and design professionals were awarded some of the coveted steel, under the condition that they use it to make public art in California.

Loughlin was one of the artists chosen. He's been working on the project for about four years, alongside a 30-person team based in Denver, Colorado. The piece will ultimately be loaded on multiple trucks for its trip to Treasure Island, where it will be put in place by a giant crane.

"Steel is the backbone of the Bay Bridge," Loughlin told Hoodline, but most people who work with steel aren't used to the level of precision that "Signal"'s construction required.

The steel has been painted with the same paint as the Bay Bridge, to protect it from the elements. Despite its outdoor placement, Loughlin doesn't believe that it will require much maintenance, besides cleaning.

"Signal" during its construction.

"Tom’s work has given new life to the 83-year-old section of salvaged steel, enabling the material to continue its humble service and benefit to the public in this new incarnation," said Jill Manton, director of the Public Art Trust and Special Initiatives at the San Francisco Arts Commission, in a statement.

"Signal"'s move to Treasure Island makes it "the first project to be implemented from the salvaged steel to be placed within [the] sightline of the Bay Bridge, its place of origin," Manton noted.

Loughlin said that he believes people are drawn to the location. "Every time I go there, there is someone there, just enjoying the view," he said. "It’s a unique place."

"Signal" will be in place until at least 2022; its survival beyond that depends on how the area changes as the Treasure Island Development Project progresses.