If you're chemically sensitive, it's probably not a good idea to get it installed, but it's also not a good idea to breathe musty air from the crawl space either. In addition, your house and its contents are made of lots of materials that affect your indoor air quality. If you're really concerned about this, hire a company to test your air and tell you what you can do about it.

Q. "I talked to a building product supplier for WALLTITE spray foam, he is suggesting to use 2" or 3" of closed cell-spray foam in the joists areas instead of the batts insulation. He says it will work with outboard rigid insulation. There is a location of a cantilevered floor area with steel beam so I may need to use spray foam to protect the steel beam. It would then be convenient continue to spray in the floor joist cavities and then apply 5" of polyiso outboard of the bottom cantilever floor sheathing."
The Gardner 4.75 Gallon Heavy Duty Foundation Coating The Gardner 4.75 Gallon Heavy Duty Foundation Coating is ideal for sealing concrete block and poured foundations fence and deck posts retaining walls and metal surfaces. Its high penetrating seal resists damage and deterioration due to moisture and insects. When applied properly this solvent-based asphalt coating helps prolong the life ...  More + Product Details Close
Liquid Rubber is generally fine when applied in one coat at a 20 mil film (42 sq ft per gallon) thickness and will still withstand extremes. That is the beauty of the EPDM polymer. A second coat would provide insurance where exposures are likely to be very extreme. Radical extremes in temperature where constant surface temperatures reach 250°F or above or -20°F or below. Warning, though, if the second coat is applied at the wrong time, it may create cracking, fissures or bubbling. The second coat should be applied either when the first coat is still tacky or when that first coat has had a chance to fully cure (up to 3 months.) https://youtube.com/v/ggLAUsiuI_o?version=3
If you cut the nails holding one of the corner studs to the bottom plate and the top plate with a Sawzall, you can use a flat bar (or a flat bar plus a wrecking bar) to pull the stud off the sheathing nails. Either re-use the stud, or buy a new stud, and install the stud with toenails as shown in the link I provided in Comment #51 (this link: Outside corner detail).
When choosing a waterproofing and sealing product, we must see to it that we can easily use and apply it using simple tools, including a squeegee or a paint roller. With ease of application, we can be certain that we can achieve hassle-free application and smoother and more attractive finish than other products could give. So when reviewing the products we have featured above, we have made sure that they are easy to apply.

Roof Coating