Sarnia Fire and Rescue Services is appealing to smokers to properly extinguish their cigarette butts.
Public Education Officer Mike Otis says along the Howard Watson Nature Trail near Home Depot is an area of particular concern.
"Well one thing for sure is that there's a lot of dry reeds in that area, so never discard a cigarette butt cause that will easily cause a fire and it spreads very fast in those areas," says Otis.
"We go to those areas for grass fires every year."
The westbound 402 was down to one lane for about an hour Monday afternoon, between Modeland and Murphy roads, while firefighters extinguished a grass fire north of the highway.
It's not known exactly what sparked the fire.
