It's silicone (not silicon, as the article misstates) so it's probably safe. Silicone is used in breast implants, home window sealants, cookware (look up silpat) and yes, fabric, as silnylon (the ultralight backpacker's waterproof friend). With the last case, it is not breathable, which is why it's not used for jackets.
I am not a breast implant expert, but if I recall, silicone fell out of favor due to fears connecting the implants to mysterious immune-related diseases. However no connection between silicone breast implants and these diseases was ever borne out.
That was alleged, but IIRC, the studies showed that there was no toxicity, and that the women with leaking silicone implants didn't have a higher incidence of problems than other women their age.
