Crews working on the new Highway 400 between Sudbury and Parry Sound are worrying about venomous reptiles as well as building a road.

The four-laning of the current Highway 69 cuts a gouge through the Canadian Shield and some of the best habitat in the country for Massassauga rattlesnakes.

"The more we work out there, the more we realize that they are everywhere," says Terri Rogers, a senior environmental planner with the Ministry of Transportation.

She says as the multi-billion-dollar four-laning project has moved north during the last 15 years and the snake encounters more frequent, special precautions are being taken to protect workers from the venomous snakes.

"Every single worker on the job site has to have some basic training that tells them what species are out there, what they look like and what they can or can't do when they find one," says Rogers, adding that there are a few dozen Massassauga encounters every year, including seven this spring, but so far, no bites have been reported.

Highway 69 four-laning

Crews working on the four-laning of Highway 69 south of Sudbury have received special training because of all the massassauga rattlesnakes they are encountering. (Erik White/CBC )

Rogers says the ministry is also taking steps to protect the habitat of the snakes and have experts on call if the construction crews need them re-located.

"We're doing a lot of different work to try to offset the actual habitat loss that the highway is causing. We are installing eco-passages to allow the snakes and turtles to access habitat on both sides of the highway," she says.

But Laurentian University biology professor Jackie Litzgus says that's easier said than done.

"You know it took nature millions of years to create those rock outcrops, all the habitats associated with that really amazing natural mosaic. So it's hard to replicate that without those millions of years," she says.

Litzgus says while the Massassauga are Ontario's only venomous snakes, serious injuries are very rare, even for those who get bit.

"They're not that dangerous. I mean the bite hurts, but it can be treated and the person usually makes a full recovery," she says.