Yeah, don't freak out. I am very anti poisons, but that is because I am very concerned about the environmental effects of them. In those terms bifenthrin is not a good thing: very highly toxic to fish, insects including beneficial ones, and plankton that are the basis of many food chains, highly toxic to honeybees, moderately toxic to a number of bird species.
It isn't very good for pets like cats and dogs that are exposed to it, where exposure means direct, either breathing it in, getting it on their skin, or eating something that was recently sprayed with it. But not very good for them means: "Clinical signs reported after pets were exposed to pyrethroids include single-episode vomiting or diarrhea, reduced activity, witching of the ear, paw flicking and hypersalivation. These signs are typically self-limiting and considered minor"
https://npic.orst.edu/factsheets/biftech.pdf
Bifenthrin is one of the synthetic pyrethroids, meaning it is based on a chemical derived from nature (from chrysanthemums) but many times more concentrated than would ever appear in nature. They are used because they are of low toxicity to humans. It is similar to permethrin which I wrote about in my thread on poisons:
https://www.helpfulgardener.com/forum/vi ... 11&t=57653
It is not very persistent in the environment. Most residues are gone after 15 days. So to be cautious, I would keep pets and small children off that lawn for a couple weeks and not harvest anything during that time. After that it should be fine, but if you want any beneficial insects like ladybugs in your garden, you will have to import them after the poison has dissipated.
So what hubby did is not a good thing, and I really don't like that he did it without your permission, especially given that the issue of poisons seems important to you, so he probably knows that. But he hasn't poisoned you and he hasn't permanently ruined your garden.