More than 100 Coast Mountain bus drivers have complained exhaust fumes from the vehicles they drive are making them sick. Some say it's so bad they've had to pull over to the side of the road to vomit. 

"Members are scared to operate those buses for fear of what the consequences might be." said Nathan Woods, President of Unifor Local 111. "The fewer of these buses on the road, the better we'll all be."

Woods claims 126 drivers have been made ill by the fumes and 19 have been hospitalized. He says efforts by Coast Mountain to modify the engines have not worked.

The vehicle in question is the Navistar International coach, a midsize 24-seat community shuttle.

A class action lawsuit filed against the company last year claims the engines are defective and pose a poisoning risk to people inside.

In an e-mailed statement Translink says 20 of the buses have been pulled off the road for inspection. That means 40 of the vehicles remain in operation in the Tri-Cities area, New Westminster and Maple Ridge.

The union wants the Navistar shuttles replaced with older models that have been decommissioned by Coast Mountain.

This isn't the first time the Navistar shuttles have been the focus of health complaints. In 2013, 25 new Navistar shuttles were pulled off the road after drivers complained of a noxious odour coming from the engine which was making them sick.

with files from Jesse Johnston