A Windsor law firm has been inundated with phone calls as a class-action lawsuit was officially launched Thursday against the company that is alleged to have improperly mixed chemotherapy drugs supplied to four Ontario hospitals.

The diluted drugs were given to nearly 1,000 Ontario patients, including 290 at Windsor Regional Hospital, over the last year. It also impacted patients in London, Oshawa, Peterborough and New Brunswick.

Two law firms, including Windsor-based Sutts Strosberg LLP, name Marchese Health Care in the class-action suit.

“Our phones been ringing off the hook,” says Sharon Strosberg, partner at Sutts Strosberg.”We are hearing from so many people who are worried, scared. They don't understand what to do or what the affect is."

Strosberg estimated at least 200 people have joined the class-action suit, but that number is expected to climb much higher.

Now that it has been filed, lawyers will have about 30 days to file a statement of claim - a more detailed document, outlining the allegations.

Windsor hospital officials say they have been working diligently to make contact with every patient impacted by this error. So far, they've reached two-thirds of the Windsor area patients.

“We've made contact with 70 per cent of patients and families,” says Windsor Regional Hospital CEO David Musyj. “We've called all of them, but some we've left messages, waiting for a call back and will call back today.”

Musyj says they’ve also received feedback from many patients.

“About half of the two-thirds have said ‘Don't worry about me. I'm comfortable with the information I have and there's no need for me to see my oncologist right now.’”

Lawyers say they have no intention of suing any of the hospitals involved.

Marchese Hospital Solutions issued a statement on Wednesday, saying: "We are confident that we fully met all of the contract requirements including both volume and concentrations for these solutions.  However, we share responsibility to ensure that patients and their families are not given any reason for concern about their treatment. We take this responsibility very seriously."