Wind tunnel testing underway as engineers work to silence humming on Golden Gate Bridge

SAN FRANCISCO - The Golden Gate Bridge is making a racket and engineers are trying to figure out how to shut it up.

The iconic span started emanating a loud hum following a retrofit last year of the sidewalk safety railing on its western side. Crews replaced some 12,000 wide slats with narrower ones, to give the bridge a slimmer profile and make it safer in high winds.

But as safety was increased, so was the noise, as gusts whipped through the new slats. Commuters, residents in the area, and visitors to the 83-year-old bridge have posted recordings of the hum online.

The noise can be heard as far away as Daly City, about 10 miles south of San Francisco.

"Some people have found it to be meditative and angelic," said bridge spokesman Paolo Cosulich-Schwartz, while quickly acknowledging that most people find it distressing.

Cosulich-Schwartz said engineers using full-size sections of the bridge railing inside a wind tunnel are working on a solution, but he couldn't provide additional details.

"We’ll have more to say this summer," Cosulich-Schwartz said. "It’s a tricky business. We want to be absolutely sure we get it right. We will never sacrifice the structural integrity of the bridge but we want to be responsive to our neighbors.’’