Spray foam insulation kits have become more popular since the 1970's. The initial cost is more than fiberglass insulation, but you will recoup the cost within 2 to 4 years, with continued savings for years after that. Spray foam insulation is made of polyurethane and is not considered dangerous. Fiberglass insulation is filled with fibers that can be dangerous if inhaled. The polyurethane insulation is not a skin irritant like fiberglass insulation is either. It is a safer alternative, as well a green alternative. It contains no ozone harming chemicals. So not only is the foam spray not dangerous, it is an eco-friendly, highly effective method.