More than 200 people have joined a B.C.-based class action lawsuit against the makers of a hair product found to contain a dangerous amount of a known carcinogen.

Health Canada first issued a warning against using Brazilian Blowout last week after lab tests revealed the wildly popular hair straightening salon treatment included 12 per cent formaldehyde -- 60 times the limit allowed by law for cosmetics.

Merchant Law Group Attorney Darren Williams told ctvbc.ca hundreds of stylists and customers have emailed the firm since the weekend hoping to join the suit they filed on Friday.

"I think over the next month we'll see more than a thousand," he said, adding the firm served papers to the California company on Tuesday.

Williams says most users experienced a runny nose, sore throat and burning eyes after applying the product. Others had shortness of breath and, in several cases, significant hair loss.

The lawsuit was initiated by Victoria, B.C., stylist Kimberley Ryley, who estimates she used the solution as many as 225 times in the past year – with negative side effects every time.

Ryley said she feels a responsibility to take legal action against a company that may harm her future health.

"We're doing this for all the stylists in Canada and across the world that could possibly have health problems after this," she said. "Maybe even cancer."

Brazilian Blowout is marketed as a "formaldehyde-free" product, and an alternative to chemical straightening products.

It is believed the chemical reactions are triggered when the solution is heated during ironing and blow-drying the hair, necessary steps in the use of the product.

On Friday, the makers of Brazilian Blowout questioned U.S. lab tests of its products, saying it incorrectly labelled an ingredient called methylene glycol, a commonly used salon treatment ingredient, as the more dangerous formaldehyde.

But even if the actual solution is formaldehyde-free, Health Canada tests found it does release the chemical during heating – its intended use. Williams said this would amount to an intentional deceit if proven in court.

"They haven't disputed the fact the solution releases formaldehyde when it is heated. It's like saying saline doesn't contain salt. It doesn't but when you boil it saline releases salt. It's the same thing," he said.

"How stupid do you think a consumer is?"

Related: Hair product class action lawsuit