My son Alex is almost one year old now, and he loves to put everything in his mouth, especially his bathtub toys. As he happily munches away on a day-glo orange crab with big Bambi eyes, I’m always a bit nervous. Surely, microscopic parts of that plastic must be getting into his system? This bath set is made in China but exported to America, from a company vowing they are “safe and dependable”, with standards that “meet and exceed” US laws. What exactly does that mean? What are these laws? Should I be worried? And just how well can I or any parent protect our children from all environmental harms?

When I think about our modern world’s reliance on chemicals and plastics, I’m reminded of what Donald Rumsfeld called the “known unknowns” – we know that we understand almost nothing about the safety of the 80,000 consumer chemicals created since World War II, because they’ve never been required to be tested on humans. As the WHO states in their 2012 report State of The Science of Endocrine Disrupting Chemicals, “the vast majority of chemicals in current commercial use have not been tested at all.”

The chief concern are endocrine disruptors, which are chemicals whose molecular structure is similar to our natural hormones. With this mimicry, they can bind to the same receptors that our natural hormones do, thus altering our normal endocrine activities which control  just about every aspect of our health. We are mostly worried about children because these endocrine disruptors could cause permanent damage during our most sensitive growth spurts: while still developing in the womb, and later during puberty. The most notorious example is diethylstilbestrol (DES), a synthetic estrogen which was given to many pregnant women in the decades after World War II as a treatment to prevent birth complications. But slowly it became clear that many newborn girls of these mothers were getting a rare vaginal cancer, and DES was banned and declared a carcinogenic — but even right now many of these same “DES daughters” are continuing to have reproductive health problems both for themselves as well as in their own children, which means some endocrine disruptors can permanently alter our DNA, affecting generations.  This is the world’s classic cautionary tale of my main concern, also the WHO’s focus: our children, and our future generations.

The prestigious JAMA Pediatrics published their own review of endocrine disruptors in 2012, essentially agreeing with the WHO’s assessment that while hard data on humans isn’t very strong, there’s enough concerning data to conclude that “efforts to reduce EDC exposure as a precaution among pregnant women and children are warranted.” Chemicals such as BPA, PVC and phthalates are most often mentioned as causing harm in boys and girls, associated with infertility, obesity, cancers and neurodevelopmental problems such as behavioral issues and a lower IQ.

The main problem with much of these “consensus” statements is that almost all of the research is from animal or lab research, and not on humans, making it difficult for anyone to truly say with certainty that similar harm would happen with humans. Mice and monkeys are not humans, as is clearly demonstrated by the great percentage of drugs which seem to work great on mice but fail to recreate similar success in human testing. I must admit that all of this medical uncertainty about our modern world’s chemicals is a bit unsettling, and I certainly hope we have stronger data in the future.

Some researchers have tried to help lessen this uncertainty, helping their test subjects to eliminate all major sources of plastics from their environment, such as from containers and canned and packaged food, and monitoring their urinary output of BPA and phthalate byproducts. The results were fascinating and disturbing. One study tried to eliminate all BPA and phthalates in a group of 20 people from 5 families, and their urine levels of those chemicals dropped dramatically. But a similar study in 2013 showed a massive increase in phthalates in the test group, a totally unexpected finding. They traced this burst of phthaletes from the coriander spice used in their prepared, “healthier” food! So there’s a classic example that “no good deed goes unpunished.” If a bunch of environmental researchers can’t even guarantee that a supposed healthier alternative is actually healthier, then how can any of us do any better?

A few consumer groups and blogs also offer helpful advice for worried parents. My favorite is The Soft Landing blog, which has a very useful collection of safer product shopping guides. I’ve also seen some good advice from the always useful Hong Kong Centre for Food Safety, which has guidelines on the use of disposable plastic containers as well as a handy PDF about the safe use of plastic food packaging and containers.The Pediatric Environmental Health Specialty Unit also offers similar advice. Here’s a small summary of what most are advising:

• Try to buy products (especially for babies) that are free of BPA, phthalates and PVC (The Soft Landing website has great blog lists)
• Switch all your plastic food containers to glass
• With the Plastic Coding System, avoid numbers 3, 6 and 7 and try to use numbers 1,2,4 or 5
• Consider buying organic produce to reduce exposure to pesticides.
• If you must use plastic cling wrap, only use PE wrap; minimize contact of cling wrap plastic with the food; and try not to microwave with the plastic on it. Especially don’t let the plastic sit on top of liquids, whether cold or hot.
• Reduce indoor dust exposure by cleaning carpets and dusty surfaces regularly using a vacuum cleaner with a high-efficiency particulate air (HEPA) filter.
• Always immediately transfer your restaurant leftovers into glass containers at home, and never reheat your leftovers or eat directly from takeaway plastic containers.

And Alex’s bath toys? While The Soft Landing blog reassuringly listed them on their list of safer bath toys, their own company rep emailed me to confirm they are “BPA-free, phthalate-free, and non-phthalate PVC”. So I am letting him munch away — for now.