I recently had to adjust the rear brakes on my 1987 nissan truck. The brake drums were stuck on and had to hit them off with a hammer. A lot of brake dust came out of the drums after getting them off onto garage floor. Pretty sure they were the oem brake pads from 1987. After getting them adjusted and putting it back together about a hour later I noticed I had a stuffy nose, sore throat and a metallic taste. I thought most of it fell on the floor, but I guess some was airborne as I had the metal taste in my mouth. So I got to looking online and it says brake pads have asbestos in them. I could have swore I read a motorcycle magazine that said they outlawed asbestos brakes in the 1970’s, but I guess not. Should have been wearing a respirator I guess, but never have for brakes. Does anyone know how really dangerous this would be to breath? I have read that asbestos in brake dust turns to forsterite and is less likely to cause damage? A lot of mixed info online not sure what to think of it all
Any dust can be bad, asbestos is real bad . It was banned in US brake shoes in late 1990’s
Ehh, the asbestos in brake dust might bother you a little but it won’t hurt you. It’s not the same as you find in old popcorn ceilings or floor tiles.
All types of asbestos are hazardous to health.
Tester
Asbestos has not been fully banned, and it can be dangerous.
It might cause you some trouble, but for the most part a single dose isn’t the problem. The big health problems comes when a person works in an area w/asbestos dust in the air all the time. Still, best to avoid breathing that brake dust, asbestos based or not, whenever possible. My car’s repair manual has a big warning at the front of the brake section about asbestos, so refer to your car’s repair manual and its warnings for future diy’er projects.
I recently replaced the rear shoes on my Corolla, and wore one of those surgical masks, you know the kind that are held on by loops around the ears, wore it the entire time I was working on the brakes. Not a burden to do, esp given the upsides of keeping the dust out of my lungs. After I removed the wheel I used a garden hose to wash the drum, front and rear. Then after I removed the drum I rinsed off the backside of the drum and the brake shoes and brake baking plate, all before starting on the job of replacing them w/new ones. A lot of dust came off w/that washing.
The only downside of the mask is that if you are also wearing safety eye glasses, the mask tends to make the glasses fog up more quickly than w/o the mask. My work-a-round for that is when the glasses fogged up I’d stop for a short coffee break.
For those of us who may get exposed to brake dust a couple dozen times in our lifetimes, I don’t worry. But I do use brake cleaner spray in a well-ventilated garage so the dust pretty much goes into a pan with liquid - never blow out brake dust with compressed air. If have less than a full can of brake cleaner on hand, I buy one or two more before tackling drum brakes.
You probably did inhale some metallic dust along with whatever the brake pads were made of. Live and learn and don’t sweat the small stuff is my advice.
I wouldn’t assume you were exposed to asbestos without testing, but if you were, you should consult physician about it.
A cut and paste from the article linked above:
A number of scientific studies published from 2002-2004 concluded that brake dust was not a cause of mesothelioma.
It is my understanding that the danger from asbestos, if any, in brakes comes from the fibers airborne during construction of the brake shoes and “arcing” them to the drum. Arcing is a process not needed on any modern day brake job. I was taught that the dust in drums has undergone some chemical or structural change associated with the heat generated by the friction of the brakes and is far less hazardous.
Tester
A simple dust mask won’t protect you from asbestos dust.
But it may prevent irritation from brake dust, the original complaint.
For that, you want a respirator (face mask with a small micron size filter), and you’re going to want a good seal with no facial hair.
The holes and inadequate seal of a dust mask do nothing but offer a placebo effect.
Thanks for the safety advice guys, but its kinda late for that now. From what I remember going to school the teachers never mentioned that asbestos was in brakes, and they never said to wear respirators doing a brake job. It seems like there would be a lot of health problems from all of the asbestos in brakes from say the 1960’s-2000’s? And from what I read most after market brake pads getting shipped into the usa still have asbestos in them. Never had a problem doing disc brakes, but this drum brake job I must have breathed in a lot of brake dust because I’m still sick with a sore throat/sinus. Although the metal asbestos taste is gone. After reading about a dozen studies online about asbestos in brake pads I am still not sure what to think. A lot of the studies are funded by the auto makers themselves.
Curiously I feel good about the placebo effect! 
3M recommends a mask capable of using their P100 filters for clutch and brake work.
A P100 filter will block 99.9% of particles .3 microns or larger.
Well there is/was asbestos in a lot of products like floor tile, pipe insulation, house siding, etc. I guess I wouldn’t worry too much about one exposure. Most of us used to blow off brake dust at one time or another. The thing with asbestos though is it’s a long term thing before anything develops. The fibers have little microscopic hooks on them like fish hooks that attach to the lungs and stick there. Over a long period of time it can cause a problem, and of course the more you have the greater the likelihood of a problem. Immediate irritation from the dust like you had is not the big issue. Back to playing with the mercury from a thermometer.
And holding lead fishing weights in your mouth when adding them to your line.
When’s the last time you walked through a cloud of floor tile dust? Just having asbestos present is no risk. It’s when it gets airborne. I remember at the gas station using the air gun multiple times to clean off drum brakes when I was in high school. Not a good idea!
With asbestos, it looks like there’s a certain fraction of the population sensitive to it that develops lung cancer. Guess I’m not part of that.