I can attest to the fact about cockroach allergens. I am a plumbing contractor who used to live and work in the Los Angeles area. There were homes in the poorer parts of the L A basin where cockroaches were VERY prevalent. Just by walking into a home I could tell just by the smell that they had cockroaches up the rear. Especially in areas like the kitchen or bathroom where moisture was more likely present. There were a few instances where the smell was so bad I felt like I was going to upchuck right there I was so overcome by it.