Once upon a time, cupboards and drawers in kitchens across the country were overflowing with plastic bags collected from grocery stores and shopping malls.
But beyond lining trash bins or being used to pick up after the dog, no one seemed to have a clear use for the mass of non-recyclable, one-time-use bags. Eventually, most would be thrown out, left to accumulate in landfills or be blown into waterways, posing risks to marine life.
Reusable shopping bags have started to change that. They're fairly durable, can be used multiple times and are quickly becoming a symbol for environmental stewardship among consumers.
For instance, Loblaw boasts it has sold more than 35 million reusable bags, a higher number than the entire population of Canada. Sobey's says it's sold more than eight million reusable bags. And that's not to mention the hundreds of other grocery stores, retail outlets and other businesses who provide branded reusable bags to customers.
But is this new breed of bag really all that good for the environment, or your health?
Many bags sold by grocery chains and other retailers require significant energy to be made and are shipped all the way from China - not exactly environmentally friendly or sustainable.
Recent revelations that many popular reusable bags contain lead have also raised questions about their safety, while concerns have also emerged about bags containing harmful bacteria.
As reusable bags grow in popularity, some experts say it's clear not all are created equal - and that consumers may want to take a critical look at the bag slung on their arm.
"We're somewhat thoughtless about this," said Rod Muir, waste-diversion campaigner with Sierra Club Canada.
In recent months, major retailers in Canada and the United States, such as Lululemon, Sears, grocer Winn-Dixie and New York-based Wegmans, have recalled, stopped selling or offered refunds for reusable bags after tests showed they contained lead.
In Canada, Lululemon said in a statement the ink used on several of its popular bags contains lead. Consumers are asked to return the affected bags to retail stores so they can be properly disposed. The company did not respond to interview requests or answer questions about its disposal methods.
Sears said in a release that lead levels in reusable bags sold in its stores last year "does not meet Sears standards" and are being recalled for consumer safety.
Lead is typically only considered a health threat if ingested, but the fear is millions of reusable bags containing lead could contaminate soil and water if they end up in landfills.
Concerns over lead in reusable bags are so great that U.S. Senator Charles Schumer has asked that country's Food and Drug Administration to investigate.
In addition, tests commissioned by plastic lobby groups have revealed some reusable bags carry bacteria that could be harmful. A 2009 study funded by the Canadian Plastics Industry Association found about two-thirds of reusable bags tested contained some bacteria, including fecal intestinal bacteria.
While many environmental groups dispute the objectivity of such industry-funded studies, Health Canada has warned consumers reusing bags can increase the chance food will come in contact with bacteria.
The environmental profile of some reusable bags also doesn't seem to hold up to scrutiny: Many of the inexpensive versions sold by retailers are made in China and shipped thousands of kilometres before reaching Canadian stores. The bags, often made out of a mix of non-recycled and recycled plastic, also require significant amounts of energy to be made.
That might not be so bad, if shoppers only kept a few on hand and used them religiously. But they've become a marketing tool for retailers who eagerly sell or give the bags away to shoppers, many of whom are now collecting reusable bags in the kitchen cupboards where plastic bags once reigned supreme.
"Retailers are trying to take advantage of the new branding opportunity presented by the reusable bag," said Rick Smith, executive director of Environmental Defence, a Toronto-based advocacy group. "I'm at the point of politely declining the free reusable bags that are being thrust upon me in the shopping malls. We don't need six dozen reusable bags."
But Dr. Smith was careful not to criticize reusable bags, despite emerging concerns about lead content, bacteria and the way some are produced. "Whatever minor problems we're seeing at the moment with reusable bags are not that big a deal in the grand scheme of things," he said.
Dr. Smith's comment highlights how ingrained the perceived infallibility of reusable bags has become, as Environmental Defence typically sounds the alarm over lead-tainted products.
A Vancouver-based reusable bag wholesaler takes issue with consumers who criticize the industry. Those same people wear clothes made in China and have the choice not to purchase reusable bags, said Randolph Yuen, owner of Smartbag Packaging. "It's the responsibility of the consumer to do what they should be doing instead of being hypocritical about the industry," he said.
But one retailer said consumers should question the validity of green claims behind reusable bags and other trendy environmental products.
"We mustn't lose our ability to question or not want to be challenged," said Trevor Smith, quality director at Green Cricket, a Toronto-based online green retailer. "Sometimes being environmentally responsible takes extra work, extra effort."