The back-to-school season is in full swing, and for parents looking to outfit their children with new school supplies, the store shelves are lined with seemingly limitless options.

With that in mind, the Canadian interest group Environmental Defence, working with the Center for Health, Environment and Justice in the U.S., last year released a back-to-school buyer's guide for parents wanting to ensure their children return to class with products that won't harm their health or the planet's.

"The stuff we buy is an increasingly important source of pollution in our lives and a pollution that is most problematic for kids," said Rick Smith, executive director of Environmental Defence and co-author of Slow Death by Rubber Duck.

"We decided it would be a great idea to try to come up with a simple list of dos and don'ts for people who are shopping at this time of year," he said.

Environmental Defence has taken particular aim at products that contain polyvinyl chloride (PVC).

"Vinyl is the poison plastic," said Smith. "More toxic chemicals go into the manufacture of vinyl, more toxic chemicals leech out and evaporate out of vinyl as it's being used than any other type of plastic. We just wanted to alert parents to that situation."

Their 13-page guide says PVC plastic, across its life cycle, is a danger to human and environmental health and is especially unsafe because of chemical additives — including phthalates, lead and cadmium — used in its production. The guide outlines the most common school supplies made from PVC, like backpacks, pencil cases and binders, and lists products made from alternative materials.

Released online in August 2009, the guide came on the heels of an announcement from Health Minister Leona Aglukkaq two months earlier outlining the government's proposal to prevent the use of six phthalates in soft vinyl toys and child care articles, including school supplies.

Phthalates are used to make vinyl soft and flexible. They can also migrate out of plastics over time, as they do not chemically bind to the material.

The provisions, if enacted, would bring Canada in line with the United States and the European Union. Both governing bodies recently passed regulatory legislation for the use of phthalates in children's toys and child care articles as a precautionary measure against potential health risks, including adverse reproductive effects and liver and kidney problems.

The concern is that children, who suck and chew on soft vinyl products for extended periods of time, may be exposed to unhealthy levels of phthalates. Although two common phthalates — DEHP and DINP — were already voluntarily removed, in Canada in 1998, from soft vinyl products intended to be mouthed by young children there remains many PVC products on the market, containing these and other phthalates, which can unintentionally end up in young mouths.

While environmental groups warn against the dangers of PVC, and governments seek to limit what can be added during its production, officials within the plastics industry continue to defend the use of soft vinyl products.

Scaring parents

"While we respect Health Canada's role in protecting the health of Canadians, we have to, as an industry, look to the science to provide us with the information necessary to keep the public safe," said Marion Axmith, director general of the Vinyl Council of Canada, which represents the interests of a broad cross section of the vinyl industry.

"The vinyl industry is based on a solid, large body of research. It's been determined that vinyl products are inert and non-toxic," she said, adding she feels the Environmental Defence and CHEJ back-to-school guide is nothing short of an effort to scare parents.

Steve Risotto, senior director of the Phthalate Esters Panel within the American Chemistry Council, agrees with Axmith's assertion that concerns over soft vinyl products are unfounded.

'The latest evidence suggests that perhaps more of our exposure is coming through air. If it's the air, in fact maybe it is some of these products that we're using. Maybe it is the pencil cases and the shower curtains.'—Dr. Miriam Diamond, University of Toronto

"You can look at what Health Canada has done in the analysis of these products, you can look at the analysis the U.S. federal agencies have done — the E.U. has done risk assessments — and there really is not a rationale for a broad phase-out," he said. "We'd just like to make sure that they go in the direction the science takes them and not respond to the political pressures."

But in which direction is the science heading?

Dr. Miriam Diamond, who runs the Diamond Environmental Research Group at the University of Toronto, said there are two main toxicological outcomes that researchers are studying. One is the relationship between phthalates in household dust and the development of asthma. The second is the role phthalates play in mimicking male hormones.

Much in the air

"Exposure in utero to phthalate concentrations — which are quite high relative to what we see in people — can lead to a number of abnormalities in male genitalia and reproductive systems," she said. "There is definitely evidence of reproductive abnormalities in male offspring."

Scientists are still unsure, however, as to how people are exposed to individual phthalates and at what amounts, said Diamond.

"The latest evidence suggests that perhaps more of our exposure is coming through air. If it's the air, in fact maybe it is some of these products that we're using. Maybe it is the pencil cases and the shower curtains," she said.

Complicating matters is the ubiquity of soft vinyl products.

"It's all over the place," she said. "It's very challenging to get representative measurements."

Although Diamond said the science isn't quite there yet to support an outright ban on phthalates, there is enough to warrant limiting exposure to them for certain populations.

"We do know, of course, especially infants and little kids are certainly more vulnerable. So for me it would be precautionary to avoid exposure for an infant," said Diamond.

"But should phthalates be limited in school-aged children?" she said.

"The truthful answer is that nobody knows."