You've already bombed your house and sprayed your yard with all kinds of toxic chemicals that you don't even know what are, and you're now researching borax because you're worried about it's toxicity? The principals of IPM are to start with the least toxic approach and then move to a more toxic approach, not the other way around.

Yes, borax and boric acid can be toxic. Almost anything can if used in the wrong way or wrong amount. You need to keep you and your pets from inhaling the dust after applying it. Vacuum daily and then throw away the bags. Don't use it outdoors as it can poison plants. It's less toxic by eons than the stuff you've already used.

Really, the best way to get rid of fleas is to use Frontline on your animals monthly, and make sure that you purchase it from your local vet, as there are lots of internet sites selling fake or expired medications out there. Vacuum daily and dispose of the bags. Set flea traps at night with a shallow pan of soapy water under a night light down low. Use an insecticide with an insect growth regulator to fog your house. Don't forget the basement and all of the spare rooms that you don't use much. IGR's will stop the development of the larvae, whereas most foggers just kill the adults, leaving the hatchlings to develop and become a problem later. I'm a board member with the humane society, and I foster all kinds of animals constantly. All of our shelter animals receive Frontline before they go into foster care, and I've never had any issues at all with flea problems on any of my nine cats or foster animals. The one time I did have a flea infestation, it was from a neighbor's dog who got into the house when I was carrying in groceries. And, that was quickly resolved using the method I outlined above.

And, I'm going to slap your hand some here. You never need to have someone apply something to your yard that you don't know what is. You need to be informed and read both the label to know the directions, and the MSDS to know the consequences of it's use. That "m something" was probably malathion, which while one of the safer insecticides if used properly, shouldn't be wholesale sprayed on your yard and everything else. I would NOT allow it to be used around my pets or children if I had any. Research your chemicals, their labeled method of application, and understand that it's illegal to use them in any manner not indicated on the label. There are tons of sites out there with information on pesticides, with Extonet being one of the more informative and less biased.

Here is a link that might be useful: Extonet

I have always used borax for flea control indoor for the larval stage.
For the adults I make a light trap. I put a pan of soapy water in middle of room at night. Put a desk lamp shining down into the water. Turn off all the lights and go to bed. The fleas are attracted to the light, just for it and fall in soapy water. Easy and cheep.

For out doors I have used beneficial nematodes. They will infect and kill the larval stage outdoors and they are organic but be sure to get the right nematode species.

!!
(::)
Buglady