BPS, like BPA, disrupts estrogen and thyroid hormones.

BPA-free plastic alternatives may not be safe as you think   by Sandee LaMotte February 1, 2016, CNN http://www.cnn.com/2016/02/01/health/bpa-free-alternatives-may-not-be-safe/index.html

BPA-free alternatives may be no safer than BPA, say researchers.   Most common alternative, BPS, linked in study to disruptions of estrogen and thyroid hormones

(CNN)Your "BPA-free" plastic product may be no safer than the product it replaced, says a new UCLA study that analyzed the impact of a common BPA alternative on zebra fish embryos. The study joins a small but growing group of similar research sounding the alarm about so called "BPA-free" alternatives.

"Our findings are frightening and important," said senior author and reproductive endocrinologist Nancy Wayne. "Consider it the aquatic version of the canary in the coal mine."

After decades of animal research linked BPA (Bisphenol A), a known endocrine disruptor, to problems with brain and reproductive development, early puberty and a rise in breast and prostate cancer, many manufacturers stopped using the chemical to harden plastics, replacing it with "BPA-free" alternatives. The most common replacement is BPS (Bisphenol S), said Wayne....
...The Breast Cancer Fund recommends that consumers wishing to limit exposure to possible toxins in BPA, BPS and other alternatives use glass, stainless steel and food safe ceramic containers for food and water storage. They stress that it's not safe to microwave in plastic. Other suggestions include using gloves to handle thermal paper receipts, and researching canned goods to find those that no longer use plastic liners.