Chunks of steel up to four centimetres in length have landed in a popular area of Granville Island.

The materials are believed to be coming from the beams of the 65-year-old bridge overhead, those who've noticed the debris told CTV News Vancouver.

Creekhouse Industries general manager David McCann said he is frustrated with the City of Vancouver.

"Twice a year they should be coming down and inspecting the underneath of the bridge for these kinds of things," said McCann. "Four-ounce piece of sharpened steel, like the one I showed you, can kill someone or seriously injure them."

A couple of days ago, McCann found pieces of steel that came off the Granville Bridge and landed on the roof of and in front of the Sandbar Restaurant.

"If you look on the ground there are hands full of these stuff," he said.

On Wednesday, a crew was deployed to inspect the bridge.

Maria Bekiaris, a spokesperson for the city's engineering department, said the crew has identified some "minor surface rust" on the bridge, which has since been removed and recoated with primer.

"Staff would like to assure the public that the structural integrity of Granville Bridge remains safe," she said in an e-mail to CTV News.

She said since no one saw where the falling rust or debris came from, the city is unable to confirm that the chunks of metal originated from the bridge.

McCann said he is not impressed with the city's response.

He said the rust that "rained down" from the bridge while crews were removing is identical to the pieces that plunged down from the days before.

"It's a cop out on their part if they're saying it's not there. There's no other material up there that would drop off to the ground," he said.

Materials have fallen from the Granville Bridge in the past.

In 2014, a piece of metal from the bridge landed on the roof of Sandbar. And in 2012, a strip of concrete fell from beneath the bridge and landed near Beach Avenue.

"I just don't want to see anybody really seriously injured," McCann said. "This is a preventable problem."

The city is currently making structural and seismic improvements to the Granville Bridge, upgrading the underside of the bridge, the steel span, north ramps and the south approach.

On Thursday, Bekiaris said in an email that the removal of surface rust on the bridge is complete, and that staff would co-ordinate a pickup of the material McCann found.

She said the pieces were looked at by city operations crews, but were not chemically analyzed. That process would help determine where it came from.