A poisonous ‘red powder’ which is believed to have sent one dog into emergency care on Saturday was found in 36 spots around Buena Vista Park but not put out maliciously, police say.

Clean up was underway the next day.

A woman called Edmonton Police Service on Saturday to report her dog had become unwell after coming across a pile of food and what appeared to be red powder along the walking bridge to Hawrelak Park.

They had gone for the walk around 2 p.m. Less than four hours later, her pet was in emergency care.

When officers investigated, they found 36 similar spots of the powder in what appeared to be, at first, no apparent pattern around the park.

Later, investigators learned the powder had been used as race markers for a running group in the Laurier and Buena Vista parks. 

The powder was a combination of bleached flour, potassium hexaflouride and D-ribose 5-phosphate barium salt – also known as land surveyors' chalk, which is poisonous when ingested.

The substance was also found near Yorath House in the park.

"The group is very apologetic and went out to the park today to ensure all the powder was removed from the ground," a statement from an EPS spokesperson read. "The group agreed to contact park rangers in advance of any future runs and ensure that only safe marking materials are used." 

Although city crews were cleaning it up, pet owners were cautioned.

“We encourage dog walkers in the park to be cautious about letting their dogs run free in the park until the city can completely clean up the powder,” EPS west division Staff Sgt. Dana Donald said.

The woman’s dog was expected to be OK.

No other complaints were made and no charges were laid. 

Police decided against closing the parks and posting warning signs. 

Park rangers noted they have seen groups use similar techniques to mark trails.