That concern comes from piles of garbage and debris in the streets of towns like Seaside Heights.
Officials are reminding homeowners and contractors to be careful of what's in there.
"We want to make sure that people are not exposed to lead, asbestos, mold, things like that, as they are repairing their homes," said Judith Enck of the EPA.
There is mold growing everywhere in places that were flooded, which is why safety officials say everyone should be using masks and gloves. Action News found one family doing just that while gutting a bungalow on Grant Avenue.
"We are wearing masks and we are wearing gloves. We know that if you get cut you could get tetanus," said Rosario Calanni. "Better to be safe than sorry."
It's not just what's growing on the walls. Health officials say mold can become airborne so, if you're breathing it in constantly, it can cause respiratory problems.
"You don't want to be inhaling it, disturbing it. You don't want to get it on your person," said Robert Kulick of OSHA.
"I have a little congestion. I think maybe that's from breathing in the dust," said Pat Calanni.
"It grows fast, that's why you've got to get in there quick and get out," said contractor Freddy Marchicco.
Monday was the first day Seaside Heights allowed full, unrestricted access. While many merchants are still clearing away what Sandy destroyed, Ryan's Deli on the Boulevard became what's believed to be the first business in town to reopen since the storm.
"The residents felt like they've lost everything and, in a lot of cases, they did. So, if we could give back just a little bit to them by giving them a place to come and use hot water and supplying them with a warm meal? It's important to be here for the community," said owner Jimmy Ryan.
Despite the fact it's December, and in the spirit of hope and rebuilding, owner Jimmy Ryan dressed for summer.
"We are the Jersey Shore, we wear shorts and flip-flips," he said. So I thought it'd be appropriate to keep going!"