Firefighters across Ontario are raising concerns about alternative energy sources, particularly solar panels.

Some say rooftop solar panels make it difficult to fight fires and can be dangerous to firefighters.

Kingsville fire Chief Bob Kissner teaches courses across Ontario on how to fight fires in the modern home. In Windsor-Essex, he also teaches a regional course on fighting fires involving structures equipped with solar panels.

He said solar panels can affect their ability to cut a vent through the roof; are, in some cases, an electrocution hazard; and can weaken, meaning it may collapse sooner than a full strength roof.

"Many of the newer homes are constructed with light-weight construction materials. They’re extremely strong but they don’t behave well in fire conditions," said Kissner, who has been fighting fires for 33 years. "If we have solar panels, it adds weight to the roof. The most important thing is to make sure the structure is able to handle the weight."

Panels also change the way firefighters battle a blaze. Kissner said firefighters can't walk on them or cut through them.

"Sometimes we need to cut the roof to ventilate and let hot smoke and gas out," Kissner said. "If there are panels there, we have to do it at the gable end."

Some of the panels simply can't be shut down by the fire department, Kissner said.

"As long as light is hitting them, they can, and likely are, producing electricity," Kissner said. "Many of the panels can’t be shut off. "We need a solar technician to kill that power.

"We can shut the power off at the inverter, but we’re always assuming the wire from the panel to the inverter is live."

Industry disagrees with firefighters

Joseph Papic of Unconquered Sun in Windsor, Ont., calls the firefighters' concerns "unfounded."

"From our perspective there is no issue. It’s more of an education thing than safety issue," Papic said.

'There is no issue. It's more of an education thing than safety issue.'— Joseph Papic, Unconquered Sun

He said the solar panels covering a roof weigh "no more than an additional layer of shingles."

Officials in the U.S. are signalling similar concerns about solar panels.

Two weeks ago in New Jersey, a massive 11-alarm fire destroyed a 300,000-square-foot food warehouse.

Firefighters had to pull back during their fight because the roof was covered in fully-charged solar panels.

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Firefighters in New Jersey said they had to pull back from this warehouse fire because the building was covered in solar panels. (Associated Press)

"With all that power and energy up there, I can't jeopardize a guy’s life for that," Delanco fire Chief Ron Holt told NBC News.

However, Papic said that once the power to a building is shut off, there is no power to the solar panels.

Municipalities tracking solar panels

Back in Ontario, the council of the Township of North Dumfries earlier this year passed a bylaw requiring all companies installing alternative energy to notify fire Chief Robert Shantz at least 30 days prior to the proposed installation.

In Windsor, Ont., a similar system is already in place. Enwin Utilities supplies information on approved solar panel installations to Windsor Fire and Rescue.

"We should be aware we’re responding to an incident with solar panels on the roof," Windsor fire department training officer Paul Acton said.

In Kingsville, though, Kissner said commercial buildings require permits for solar panels. But the same isn't always true for residential buildings.

"The issue is that if a homeowner decides to put them on, there may or may not be a permit pulled. It may be difficult to see them," Kissner said.

Nearby Tecumseh Fire and Rescue expects problems to eventually arise there, too.

"You're starting to see, when you you drive down every street ... more and more solar panels going up," Tecumseh firefighter Nick Jovanovic said.