The company carrying out the province's roadside spray program is defending the chemical it uses.
Tordon 101 is being used to control the growth of brush and trees along the highway.
But critics fear the chemical can harm people.
'I've got 20 years experience with Tordon 101 as a vegetation manager, and Tordon 101 is one of the safest products that we have used.' —Terry Croucher
Terry Croucher owns Newfoundland and Labrador Vegetation Control, which has the roadside spray contract.
"I've got 20 years experience with Tordon 101 as a vegetation manager, and Tordon 101 is one of the safest products that we have used," Croucher said.
"We've had zero incidents with this product when applied properly."
Croucher says studies have shown the chemical has less of an impact on human health than either cigarettes or salt.
"I've got to trust Health Canada," he said.
"I trust them for everything else. When I go to the doctor and a doctor gives me medication, Health Canada OKs those, so I've got to trust them. Either I believe in science or I don't."
Croucher contends the chemicals being sprayed on farm crops in this province are more dangerous than what's being used along highways.