ST. PETERSBURG, Fla. -- One of the dangers of any hurricane isn't just the strong winds, but the potential for heavy objects to be picked up by that wind and turned into a missile. That is why Tampa Bay's construction boom could make the threat from Hurricane Irma even worse.

Wind speeds of 150 mph are dangerous enough. A two-by-four traveling at that same speed can be deadly.

“I wouldn't want to be near it,” said Kathy Wallen, looking up at a hi-rise under construction in downtown St. Petersburg.

The potential for deadly if not damaging debris has a lot of worried people looking up, wondering about so many buildings under construction vulnerable to Hurricane Irma's ferocious winds.

Colleen Conklin, staying at a hotel near the new One St. Petersburg project, says she’s worried about “everything falling down. And people getting injured. This place is so busy,” she said.

St. Petersburg Mayor Rick Kriseman says his office has reached out to contractors, urging them to do everything they can “to start securing their equipment, building materials -- everything they can. So that that stuff doesn't become a weapon,” said Kriseman.

In Tampa, Mayor Bob Buckhorn says it's the same. Public projects under the city’s control, like the facelift at old City Hall, have already started storing loose articles and building materials.

Buckhorn says he’s confident many of the contractors, based in South Florida, have plenty of experience with storms, and will do what’s necessary.

“Recognizing that in 100 mph plus winds, I don't know what you're gonna be able to do,” said Buckhorn.

Residents also have an obligation to be good neighbors by getting rid of trash and debris, and bringing in furniture and other items from outside patios that can turn into projectiles.

That’s what happened in 2013 when a weak tornado moved through downtown Tampa. It was still strong enough to pick up patio furniture on high-rise balconies, hurling it onto the streets below in Channelside.

That was just one location.

“Yeah, it would be scattered all over the town,” said Kathy Wallen, concerned about all those loose building materials. “I mean, people would get hurt. A lot of injury potential,” she said.

At two of the most active construction sites in Tampa and St. Petersburg, workers say they have been in clean-up mode for the last two days.

But those giant cranes with massive counterweights towering over the skyline can’t be moved in time. In South Florida, people are already being urged to keep their distance.