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.   Spray Coating

When using this roof coating, two coats are required. It doesn’t take much time to apply the coating. If the weather is not humid, the coating will take only a few hours to get completely dry in full sun.This coating can go over and hold strong on the sealing tapes. This feature helps you to restore your roof to brand new. It may save thousands of dollars from replacing your old roof. Coating Services
When intumescent coatings are used with spray foaminsulation, they are specific to each insulation brand. You cannot use one intumescent coating with a brand that it was not intended for. If you do not use the properspray foaminsulation brand and intumescent coating combination, then your work will not technically be up to code. Additionally, it is important to keep in mind that intumescent coating can only be used as an ignition barrier alternative if it is being used in an attic or crawl space. And, even then, it can only be used if space is not used for storage and is accessible through a small hatch or door. Spray Coating
Thermal barriers come in the form of 1/2-inch gypsum drywall or any material that is proven to have an equal fire resistance to gypsum wallboard. Additionally, alternate assemblies can be used if they have been tested in a laboratory and approved. Ignition barriers are a lower standard to meet, and can be satisfied with a number of different materials. Like thermal barriers, they can be substituted with equivalent fire resistant materials and alternate assemblies, such as an intumescent coating.

The video below is from a house near Charleston, South Carolina that I visited recently, and you'll see that the homeowner in this case didn't get his money's worth. I knew immediately when I walked into the attic that something was wrong because it was hot up there. In a properly insulated spray foam attic, the temperature won't be much higher than the house temperature. 

A rule of thumb puts two thirds of the coating on the substrate and one third in the air. True HVLP guns use 8–20 cfm (13.6–34 m3/h), and an industrial compressor with a minimum of 5 horsepower (3.7 kW) output is required. HVLP spray systems are used in the automotive, decorative, marine, architectural coating, furniture finishing, scenic painting, and cosmetic industries. Spray Coating