Having raised children myself, reading this recent Discovery.com article about the high phthalate content in PVC materials in school binders, backpacks and other plastic items used by our kids every day sends out big warning signals. Phthalates are used to soften plastics. Many toys and other items with phthalates were banned in Canada, the US and EU but the product continues to be used in the production of school supplies and clothing.
"Vinyl lunchboxes, backpacks and even 3-ring binders were among the 75 percent of supplies tested by an independent laboratory for the CHEJ that were found to have elevated levels of the endocrine disruptors. Research has linked phthalates, which are used to soften plastic, to birth defects, obesity, asthma and infertility, among other ailments. Some were banned in toys in 2008." news.discovery.com/It's buyer beware, especially since many products do not list phthalates in the contents labels. Phthalates are also found in food wrap, vinyl lunch boxes, modelling clays,thermoses and water bottles, office supplies, shiny rain gear, electronics and plastic eating utensils. If you sew things for your kiddies or for crafts be sure to ask for contents info from fabric suppliers, too.
For more info check out this pdf publication produced by the Center for Health, Environment and Justice. It also contains a green list of safe products, how to determine what has PVC content and related data and info. Well worth spending a few minutes to read.
Update Dec 2014: This website notes it's best to avoid microwaving foods in plastic, and avoiding using items with scented products "as much as possible, including air fresheners, and dryer sheets, and not using recyclable plastics labeled as 3, 6, or 7".