Concur with previous poster. Thumbs up for food-grade diatomaceous earth! I got a box from Arbico Organics when the dogs got fleas. Swept it into the floorboards, sprinkled under mattress pads and on upholstry, hoovered it up after 24 hrs. Brushed it into the dogs' fur, no problemo if they ate it (some people put it into dog, horse, etc. food to control worms. Some people even sprinkle it on their cereal cuz they think it helps their digestion!!). We all eat it, actually -- farmers put it in grain bins to kill pests.
I wore a a paper mask whilst sprinkling just in case, and kept away from the doggos' heads so as not to irritate eyes or noses.
I also ordered beneficial nematodes (they come in a little dried cake and you mix them with water to reanimate them) and sprayed them on the yard with a fertilizer hose attachment.
No more fleas, without any sprays, bombs or other chemical stuff.