After laboratory tests revealed traces of lead in reusable shopping bags sold in B.C., many consumers are wondering how to make sure their bags are lead-free.

Lead levels in the four grocery bags randomly chosen for testing by CTV News ranged from five parts per million in a Thrifty Foods bag to more than 1,000 parts per million in one from Whole Foods.

"There's a wide variance in the lead levels in these bags, but some of them are quite high -- surprisingly so," said Dr. Tim Takaro, a health sciences professor at Simon Fraser University.

Health Canada has not set limits on how much lead is allowed in reusable bags, and says it's up to companies to make sure their products are safe.

But Takaro says a cautious approach is best for consumers.

"Any amount of lead for a developing fetus is thought to be a problem, so we want to achieve as low lead levels as possible, and a consumer product like a grocery bag shouldn't have lead in it," he said.

Reusable bags, usually considered to be a "green" alternative to plastic, can't always be disposed of in an environmentally friendly way, either. Many are made of a fabric-like material called non-woven polypropylene, which can't be recycled, according to the Recycling Council of B.C.

Many retailers import their bags from overseas – particularly China -- but Vancouver resident Jenny Hughes offers a local alternative.

Her bags are made of natural and recycled fabrics, but they come at a higher cost.

"To spend $20 to $30 a bag, it is a bit more, but when you're getting one of my bags they're going to last you your whole life and you're going want to carry them around," Hughes said.

With a report from CTV British Columbia's Maria Weisgarber