Jennifer, I'm not an expert on the health effects of closed cell foam. A lot of people live in houses with closed cell foam and have no health problems from it, at least not short-term, acute problems. I do know of one person who had it removed from her crawl space because she was convinced it caused her dog to get sick, but I know only what she told me.
I applied this product on a rolled asphalt flat patio roof. It was over 90 degrees and I could not touch the roofing at all on the first coat. I was laying on layers of cardboard to apply the silicone under the gutters and then rolled the first coat. The next day I brought all the cardboard to apply the coating under the gutters. I accidentally touched the roof and it was coolâ€¼ï¸ I threw the cardboard off the roof, laid down to do the gutters and roll the second coat. I was amazed how well this sealed and cooled the patio. I am going to apply this to my other patio and covered parking which are metal. I can’t wait to apply for sealing and adding cooling to these areas. Roof Coating Supply answered all my question and they ship promptly - I had my order in 3 days. Thank you.
As this example illustrates, it's important to seal the envelope completely. One of spray foam's biggest selling points is its air-sealing ability, but it can't seal places where it's not sprayed. One of the nice things about using spray foam in new construction is that you can do a Blower Door test before the drywall goes in. Even better, you can test for leaks with a fog machine. Spray Coating