With power outages possible because of the nor'easter, authorities say those with portable generators should be careful.

Although portable generators can help in bad weather, experts say they must be used safely.

“The biggest mistake we see people make is they try to use them in their houses or inside their garages, perhaps with the garage door propped open,” says Consumer Reports Home Editor Paul Pope.

Each year, hundreds of people die from carbon monoxide poisoning, with the cause sometimes being an improperly ventilated generator.

“Because they're burning gasoline, they emit co which is totally odorless and can be deadly in as little as a few hours,” says Pope.

Pope says to use a portable generator safely, the generator must be kept at least 15 feet from the home.

He says to never use a generator inside your home or garage, even with doors and windows open.

Also to always make sure the homeowner has carbon monoxide detectors in their house that can work even if the power is out.

Finally, he says to always let the generator cool down before refilling it with gasoline.

“The heat can actually cause spilled gasoline to ignite and cause a fire,” he says.

For those who wish to have their generator power a furnace, stove or appliances, they'll need to have an electrician install a transfer switch from your main electrical panel, which is something best done well before a storm.