"It's just part of the process, it's part of our job, and it just happens that this check that we made had a broader impact than we certainly would have anticipated," Craig Woudsma, 28, said Tuesday.
"But definitely not a hero, no."
The pharmacy team in the small Peterborough hospital that caught the problem didn't want to go public with their story initially, according to hospital officials.
"We're not looking for glory or anything like that," Woudsma told an Ontario legislative committee that's investigating the drug scare.
"What we do is kind of the same thing day in and day out, and we're there for the patients. We didn't want to add to the spectacle that it kind of became."
Woudsma, who was certified as pharmacy assistant in 2007 and started working in the hospital's oncology department in 2011, said he started asking questions when he saw the bags from Marchese Hospital Solutions required refrigeration.
Another pharmacy assistant noticed that the bags containing the drug-and-saline mixture from the previous supplier Baxter didn't need to be refrigerated, but the new ones from Marchese Hospital Solutions did, Woudsma told the committee.
It was the first day the hospital was using the Marchese mixture, so he compared the labels on both bags, he said. He noticed that the labels on the Marchese bags didn't provide the total volume or the final concentration like the Baxter labels.
He also noticed that the electronic worksheet used to calculate the dose for each patient used the final concentration indicated on the Baxter label.
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 patients in Ontario and New Brunswick had been receiving the diluted drugs for as long as a year.
Woudsma said he's surprised that the problem was so widespread. But the affected patients should know that things will change.
"It's going to tighten up some things that we didn't know weren't very strict," he said after his testimony.
"So it's an unfortunate situation for everyone to be in, but I think at the end of the day, there is a silver lining that it will help further on down the line."
Ontario and Health Canada have acknowledged that there was no oversight of Marchese Hospital Solutions and don't know how many other companies like Marchese are operating in Canada.
Marchese has said it prepared the drugs the way it was asked to under its contract and under the supervision of a licensed pharmacist.
But Medbuy, the bulk purchaser that arranged the contract, said Marchese didn't meet the contract's requirement to provide an exact concentration of the drugs in the saline solution.
Progressive Conservative health critic Christine Elliott said she believes it was a mutual mistake.
The contract "wasn't necessarily as clear as Medbuy would have thought it was, that there was perhaps some leeway for Marchese to have assumed that the product that they supplied was adequate," she said.
Bags of saline usually contain some extra liquid to account for evaporation. But Marchese didn't account for it, thinking each bag would be given to a single patient, the committee heard. Their labels also didn't indicate how much additional saline was in the bag.
The hospitals were extracting fluid from the bag to prepare chemotherapy treatments for different patients, unaware that the drug mixture had too much saline.
Woudsma said the Marchese labels were "vague," so he brought it to the attention of the pharmacist and senior pharmacy assistant Judy Turner. She called Marchese for clarification, and was told they thought the bags were being administered to a single patient, the committee heard.
It's "very concerning" that a massive health-care system with very qualified people didn't catch a problem that a young pharmacy assistant managed to uncover, said Elliott.
"We need to make sure that we have all the checks and balances necessary in the system to make sure that mistakes like this don't happen."