If you snorted a line of nesquick one time you might get your sinuses stopped up for a while and taste chocolate flavored loogeys and drains. Maybe a little blood in your snot if your sinuses are already irritated. Not really much a health hazard there since that one line will probably be the one and only you ever do.
This is what happened to me and other people I know. Snorting coke, meth, or pills once or regularly can possibly make your nose bleed, cause infections and ulcers in your sinus cavities, throat, and back of tongue. Its drips down the back of your throat and mouth irritating and causing raw bumps and ulcers. Sinus infections are common especially after snorting or inhaling large quantities of drugs or dust. After snorting a bunch of cocaine I usually woke up with a killer sinus headache, totally stopped up with really nasty yellow snot sometimes with blood in it. Larger quantities of powdered cocaine are inhaled by users generally than users of other nasal drugs. Its made by barefoot peasants stomping it barefoot in the jungle. No telling what bugs are in that shit! Extended prolonged use will eat large holes in your sinuses and nasal septum even to the point of your nose collapsing into your face. I have a small hole in one side of my septum that is not noticeable and causes me no problems. Also the drainage of coke and meth from your sinuses to throat ends up in your mouth on your teeth is acidic and can eat away at your teeth. Fortunately I never got the very ugly condition known as meth mouth.
Not wearing a dust mask doing dusty jobs like cutting bricks, concrete, sanding drywall, and other dusty jobs will do all the above also. Some of those dust contain silicates and fibers which actually lodge in the sinuses. If you do drugs the best advice I can give is no pills, no powders, if it grows from the ground its okay.