Toronto police and fire officials have managed to clear up a sulphuric acid spill that caused a dangerous, toxic mist in the air in Toronto’s west end Thursday.

It’s now safe to go outside, Toronto Fire said.

Eight people were treated for minor throat and eye irritation, but no serious injuries were reported, Toronto Fire said.

The incident was reported a little after 10 a.m. at Paton Rd. and Wade Ave., northwest of Bloor St. and Lansdowne Ave. Callers described a “fog in the air” and difficulty breathing, said Const. Allyson Douglas-Cook of the Toronto Police Service.

Toronto Fire Services said a small amount of hydrochloric acid had been mixed “in error” with a large concentration of sulphuric acid inside a building, causing a “fog” in the area. Paramedics were also called to the scene.

Area resident Danny Nguyen said he was passing by when he heard about the fog. He said he stayed on the corner to watch the scene unfold, and was “a little freaked out.”

“Earlier, above the building, the sky was blurry,” Nguyen said.

After the spill, buildings in the industrial area were evacuated. Roads were blocked off in the area while 25 firefighters got rid of the mist – a tricky task, given that sulphuric acid reacts violently with water.

Toronto Fire said it was mostly a matter of keeping people away while the chemical reaction fizzled out.

Meanwhile, a TTC bus on the corner of Lansdowne Avenue and Paton Road acted as a temporary shelter for about 40 evacuated employees.

Sulphuric acid, a clear, colourless, odourless and oily liquid, is “very toxic” and corrosive, according to the Canadian Centre for Occupational Health and Safety (CCOHS). It’s mainly used in battery acid, fertilizer manufacturing and petroleum refining.

Eye or skin contact with the substance can cause burns, pain, redness and blistering. Ingesting sulphuric acid can cause internal burns and permanent damage or death, as can inhaling it, should the material be heated up or misted.

Long-term damage can result from even a short exposure, CCOHS said.

Hydrochloric acid is also potentially lethal if inhaled, and can cause severe damage to the eyes and respiratory tract. It can also cause burns, and may be corrosive to metals.

Samantha Anderson, the manager of the Starving Artist, a small restaurant on the corner of Lansdowne Avenue and Paton Road, said neighbours were told to close their windows and doors but the restaurant was not told to do anything.

She said it had otherwise been a "pretty slow morning.”

“It makes me a little nervous,” Anderson said of the spill.

“I’ve been feeling a little woozy but it’s probably all in my head.”

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According to Anderson, those dealing with the emergency "seem relaxed," which she said put her more at ease.

The scene was declared safe and residents allowed back outside at around noon. However, the road remained closed as clean-up continued.

−With files from Ellen Brait