Toxicity concerns typically focus on one chemical at a time, due to the way our legal, science, and regulatory systems have been set up. But in the real world, dozens, hundreds, or thousands of chemicals interact to increase or decrease actual toxicity, in ways that can be very different from expectations for the individual chemicals.
This issue is illustrated well by the current controversy over bisphenol A (BPA), which is found in many plastics. The great majority of the science looks just at BPA. But plastic products often are made of dozens of substances.
To evaluate the combined effects of all ingredients in a plastics product, via one route of toxicity, a team of researchers evaluated more than 500 such products for their ability to induce estrogenic activity (EA, the most common form of endocrine disruption). The products were purchased at stores such as major mainstream retailers (e.g., Wal-Mart, Target, Albertsons) and ones that tend to appeal to more health-oriented customers (Whole Foods, Trader Joe's). The researchers found that nearly every product induced EA, even all the BPA substitutes.
At the same time, the researchers discovered there are some plastic products that instigated no EA in their tests, and would cost about the same to use in lieu of the EA-inducing products.
- "Most Plastic Products Release Estrogenic Chemicals: A Potential Health Problem that Can Be Solved,"  by Chun Z. Yang, et al., Environmental Health Perspectives [doi:10.1289/ehp.1003220]; George D. Bittner,  512-339-0550, ext. 201.
Keep in mind that most of the researchers are employed by a company, PlastiPure,  that has a vested interest in selling non-EA products. Also, keep in mind there are other modes of toxicity besides EA, so any product that passes the EA screen would also need to be evaluated for carcinogenicity, immune disruption, neurological damage, etc.
You can cover this research and issue explicitly as a direct consumer story, for products on shelves today, or as a hook for a big-picture assessment of the limitations of our current legal, regulatory, and science systems.