TORONTO -- Health Canada says it is holding the 300,000 Johnson & Johnson COVID-19 vaccine doses that arrived in the country on Wednesday due to a possible quality control issue.

In a statement issued on Friday, Health Canada said the vaccine doses are being held for further review after learning that a drug substance used in the vaccine was produced at the Emergent BioSolutions' Baltimore facility, which had an error last month that led to millions of J&J doses being ruined.

"Health Canada has learned that a drug substance produced at the Emergent site was used in the manufacturing of the initial Janssen vaccines received on April 28 and intended for use in Canada. The drug substance is the active ingredient that undergoes further processing before becoming the final product," the agency said.

Health Canada noted that the final Janssen vaccines were manufactured at a different site located outside of the U.S., however, the agency says it will review the doses to ensure they meet quality standards before they are administered to Canadians.

"As with all vaccines imported into Canada, the Janssen vaccines will only be released for distribution once Health Canada is satisfied that they meet the Department's high standards for quality, safety and efficacy," Health Canada said.

The agency added that it is currently working with Janssen and the U.S. Federal Drug Administration (FDA) to "obtain all of the information it needs to complete this assessment, prior to releasing the Janssen vaccines for distribution."

Canada’s J&J doses were expected to be distributed to provinces next week, but no new timeline has been given as to when the shots will be released.

The FDA had stopped AstraZeneca from using the Baltimore facility earlier this month and halted production of J&J’s vaccine at the plant as it began investigations into "multiple areas of concern," including a vaccine ingredient that did not meet quality standards.

Health Canada said on Sunday that the 1.5 million doses of the AstraZeneca COVID-19 vaccine imported from this facility were safe and met quality specifications.

The agency has reiterated that it "remains confident" the imported AstraZeneca doses are safe after reviewing test results of all vaccine lots that came into the country.

Health Canada said it has "rigorous processes in place to continually monitor the quality of vaccines that are administered to Canadians."

"We will continue to ensure that products coming from the Emergent facility, or any other facility, will only be imported and distributed in Canada if they are of high quality and safe for use," Health Canada said.

Correction:

This story has been corrected to clarify that a drug substance used in the J&J vaccines was produced at the Emergent BioSolutions' Baltimore facility. The story previously stated that the vaccines themselves were imported from the facility.