An impromptu foam party stopped traffic just west of Toronto late last week in the form of soap suds spewing forth from sewer grates, messing up many a Friday night commute and leaving everyone to wonder, "why?"

It took officials in Mississauga a few hours to get an answer, but they weren't taking any chances in the meantime.

"Dangerous Condition / Foam Party," tweeted Peel Regional Police at 7:21 p.m. on Jan. 6, 2023, warning of lane reductions and closures in the Dixie Road and Dundas Street East area.

"It's not actually a foam party so please avoid the intersection while we figure out the problem."

What cops did know at the time is that some type of "suds" had been coming out of sewers in the area.

DANGEROUS CONDITION/FOAM PARTY: 🧼

-Dixie Rd/Dundas Street E #Mississauga
-Suds coming from sewers in the area
-Lane reductions and closures
-PR230006322
-It’s not actually a foam party so please avoid the intersection while we figure out the problem. pic.twitter.com/bNdQlxYXah

— Peel Regional Police (@PeelPolice) January 7, 2023

As it turns out, the suds were made of "some kind of industrial soap" that proved not to be dangerous.

Peel police announced just before 10 p.m. that the foam party was over and that all roads had reopened.

Mississauga fire crews came to hose the roads down, leaving them squeaky clean... until Peel Region sent along salters to prevent ice from forming on the freshly-lathered asphalt.

Ironically, some roads in Mississauga were hosed down heavily the day previous by severe flooding.

WATER-MAIN BREAK:

-Lakeshore Rd closed between Lorne Park Rd and Mississauga Rd in #Mississauga.
-Heavy flooding
-No Injuries reported
-Crews are on scene trying to fix the issue.
-Please use alternate routes
-PR230005129 pic.twitter.com/DIprhJSp7x

— Peel Regional Police (@PeelPolice) January 5, 2023

When asked on Twitter by a local biologist if the soap will enter local waterways and reach Ontario, the Credit Valley Conservation Authority couldn't say for sure what would happen.

"Without knowing exactly what / how much there is, it's tough to say what the impacts might be," wrote the conservation authority. "While not good, it might be diluted enough by the time it gets to Lake Ontario that there may be no fish issues."

Anyone can report spills like this one to Ontario's Spill Action Centre online.

Where the foam came from remains unclear as of Monday morning, but some people have theories.

"When I lived in Verdun (Montreal, Quebec), people would put soap flakes in the fountain in front of the city hall/police station," ventured one Twitter user. "Maybe someone thought this would be funny! Odd how it was flying out of the sewer!"

"Isn't there a car wash nearby at the gas station?" asked another. "The detergent they use does foam up a lot and a spill from one of their drums of soap would probably do that."