Companies that issue reusable bags found to contain lead in testing performed by CTV News are reassuring customers, and one retailer is challenging the results.

In random tests performed at BCIT, bags used by IGA, Whole Foods, Toys ‘R Us and Thrifty Foods were all found to contain some lead.

The highest levels were found in the Whole Foods bag, with 49 parts per million in the cloth and more than 1,000 parts per million in the logo.

In a statement, the grocery company says that it performs its own tests of the bags. The most recent test, performed in September, showed levels of less than five parts per million, Whole Foods says.

"Whole Foods Market is dedicated to stringent quality standards for the all the products we sell, including our reusable bags, and we have found no issues with any of them," the statement reads.

The company goes on to say it has concerns about the accuracy of the BCIT tests, but will perform more third-party tests "out of an abundance of caution."

In the BCIT tests, Thrifty Foods' bags were found to have much lower levels of lead -- between five and 10 parts per million.

NTake EcoDurable Products supplies the grocery store with reusable bags, and the company's Tony Towers says it sets its allowable lead limits based on Health Canada's standards for children's toys: 90 parts per million.

"Lead is used in the silk-screening, mostly, that puts on the artwork for most of the bags, but it's also used in the material," Towers told CTV News.

"We've been aware that there's lead levels in bags, and quite frankly there's lead in practically everything in our environment -- it's one of the ambient properties that surrounds us. But there's a difference between lead levels, as far as we're concerned, and too much lead."

NTake posts its test results publicly online.

Health Canada says that it is not aware of any reported concerns related to lead content in reusable grocery bags, but it is now reviewing the issue.

With a report from CTV British Columbia's Maria Weisgarber