TORONTO - An Ontario pharmacy assistant who discovered the diluted chemotherapy drugs that were given to more than 1,200 cancer patients in two provinces says he started asking questions when he saw the bags required refrigeration.

Craig Woudsma of the Peterborough Health Sciences Centre says another pharmacy assistant noticed that the bags from a previous supplier didn't need to be refrigerated, but the new ones from Marchese Hospital Solutions did.

He says he compared the labels on both bags and noticed that the new bags containing the drug-and-saline mixture didn't provide the total volume or the final concentration.

It was later discovered that the bags contained too much saline, which watered down the prescribed drug concentrations by up to 20 per cent.

Some of the cancer patients in Ontario and New Brunswick were receiving the diluted drugs for as long as a year.

Marchese has said it prepared the drugs the way it was asked to under its contract and under the supervision of a licensed pharmacist.