The rubber itself of some boots have a strong chemical odor. I realized this several years ago while in a Cabelas store. I was looking over a pair of boots that I was considering and I caught a whiff of something odd. I sniffed the boot soles and they indeed had a strong odor. At that point, I decided to check some other brands/models. Some were odorless and some were not. A sales woman saw me smelling the boots and asked me what I was doing. Haha, I think she thought I was nuts (she was very perceptive! LOL), until she sniffed one and then she knew what I was talking about.
I'm not sure if that odor would be something that would alarm deer or not. In most habitats, deer encounter chemical odors on a daily basis. I'm beginning to believe it's not chemical odors that alarm deer it's predator (human) odor that alarm deer. But why tempt fate? I still try to reduce all odors.
While we are on the subject, the common practice most hunters employ is to store boots in air-tight tubs and I do as well but with a caveat.
I only store dry and deodorized boots in an air tight tub. After each hunt, the inside of rubber boots are going to be damp with sweat, which will grow bacteria and stink. I do not want that boot enclosed in my air tight tub. I feel the odors from the inside of the boot will contaminate the entire boot, inside and out and will contaminate the tub as well.
On the drive home, I leave the lid off the tub until I get to my boot dryer. Boots have to be put on a dryer after every use. As soon as I get up the next morning, My dry boots go back in the tub and I run a short, 5-10 minute ozone cycle into the tub with the lid on. Yeah, O3 is hard on rubber but only if the rubber is exposed to O3 for extended periods of time. If I'm not hunting that day, I'll run the O3 and then air-out the boots immediately after. The O3 has done it's job so there is no need to store anything in a sealed environment of O3. After the boots air out, I close the tub and store it.
If I am hunting that day, I'll leave the boots in the closed tub for the short drive to my parking area and get dressed.
This regimen has not shown to have much, if any effect on the rubber.
Is it worth doing this? I think so. Busts from my ground odor are zero since I've started doing this a bunch of years ago. I firmly believe the only thing deer are smelling when they cross my trail is the odor of "ground disturbance", and not human odor. Do I leave human odor on the ground? Maybe, maybe not. I know all the arguments about tests with dogs. But I do, 100% know, that before I started doing this most deer would lock-up, or panic when they hit my trail. That never happens any more. Coincidence? Doubtful.