Hey guys -- Jonathon Stewart here for About.com. Polypropylene, polyethylene, polyvinyl chloride and di(2-elthylhexyl)adipate - when you hear these words, I know what you're thinking. Who gives a flying polycarbonate? But the word on the street is that some plastics are safe and recyclable and others have been proven to leach dangerous chemicals into your food. The good news? They're real easy to tell apart. Check it out.
Plastics and Recycling
Plastics are widely utilized for their durability, flexibility, and versatility and in 1988, the Society of the Plastics Industry responded to pressure from recyclers to classify these types of plastics and the SPI Resin Identification Code was born.

Now this is where it gets fun, in a Where's Waldo sort of way. On any piece of plastic that follows the SPI Code, you'll find a number between 1 and 7 in a little triangle, which corresponds to the type of resin used in its creation.
Types of Plastic
Since the SPI Code rules fall under state by state jurisdiction in the US, there's no official federal regulation with regard to its use. But, when you do see a number, here's what it means, and -- according to authorities like the National Geographic's Green Guide and countless other watchdog groups -- which ones you should avoid:

#1 includes disposable soft drink and water bottles, and is okay for single use and is generally recyclable. #2 includes milk jugs, liquid detergent bottles, and shampoo bottles, and is considered safe and is generally recyclable.

#3 includes meat wrap, cooking oil bottles, and plumbing pipes and contain potent carcinogens and hormone disruptors which are linked to negative effects on the liver, kidney, spleen, bone formation and body weight. #3 is also the least recyclable.

#4 includes cling wrap, grocery bags, and sandwich bags, and while it may be tougher to recycle than 1s or 2s, it is not known to leach or transmit any chemicals.

#5 includes cloudy plastic water bottles including some baby bottles, yogurt cups, and straws, and like #4 is hard to recycle but safe for use.

#6 includes disposable coffee cups and styrofoam take-out containers, and has been known to leach styrene, which can be toxic to the brain and nervous system. #6 is also tough to recycle.

Finally , #7, or "other" includes plastics that were invented after 1987, and is found in some baby bottles, some reusable water bottles, and stain-resistant food-storage containers, and may or may not contain Bisphenol-A, or BPA. Studies suggest that BPA may stimulate prostate cancer, produce ovarian dysfunction, or result in genetic damage, and has even been linked with heart disease and obesity.
Plastic and Food Safety
How much should you worry about all this? Well, the FDA has yet to concede that any of these plastics are necessarily bad for you, although they do admit that some plastics can leach into your food, just in really small amounts. They also suggest that when microwaving food in plastic wrap, that the plastic wrap shouldn't actually touch your food. That's convincing.
Avoiding Toxic Chemicals
To reduce the risk of exposure to toxic chemicals in plastic, follow these simple guidelines: 1) Remember the 3-6-7 rule: be sure to check any plastic, from food packaging to baby bottles, for its SPI Code, and steer clear of these potentially bad plastics. 2) Switch over to storing food or liquids in glass containers, and make sure any plastic lids you use are either a 1, 2, 4, or 5. 3) Be on the lookout for plastic-lined cans, which may also contain BPA, and 4) Never microwave anything that's in or near plastic or plastic wrap.

Just remember that if you do all this, you may get called names like "worry-wart" or "dork." But you can also sleep peacefully knowing you don't have anything called Bisphenol-A roaming around inside your baby.

Thanks for watching! To learn more, visit us on the Web at About.com.

https://video.about.com/housewares/Plastic-Food-Containers.htm#vdTrn