Is Smoking Safe? (in a galvanized garbage can)

I'm hoping there is a scientist out there who can answer this. This is my question:

I've been smoking meat and fish on occasion for the last 35 years. My favorite smoker was a full sized galvanized metal garbage can with an inch or so of beach sand in the bottom, a few holes for air near the bottom, and 4 stove bolts about 4 or 5 inches from the top which held up a cheap BBQ grate. I'd light about 4 briquettes, and then when they were going but hickory blocks on top of them; put the grate on top sprayed with Pam and put the meat or fish on top of that--Usually blue fish. After a while the interior had like a black glaze on it.

I had another one that was electric (I think Meco, or something Cooks (yuk) recommended) but the electric element burned out the day it went out of warranty.
Does anyone hae thoughts on the safety of using a galvanized metal garbage can? It doesn't really get that hot as the heat is on the sand? Aren't some of those Tamale buckets galvanized?