Salt production: http://www.saltinstitute.org/salt-101/production-industry/ http://www.saltinstitute.org/salt-101/production-industry/ A lot of the salt (~80%)

Salt production: http://www.saltinstitute.org/salt-101/production-industry/ http://www.saltinstitute.org/salt-101/production-industry/ A lot of the salt (~80%) produced in the US goes to road salt and chemical industries. For roads it's better if it's in rock form, so a lot (if not most) is mined. For chemical industry they can often re-use brining wells to hold other things later, so the great majority of chemical salt is brined. Salt mines: https://en.wikipedia.org/wiki/Salt_mining https://en.wikipedia.org/wiki/Salt_mining Of all the salt production methods, non-brine mined salts have the least toxic or harmful byproducts - at the source. But they still go through processing plants to sift, grind and package the salt, and not every processing plant has the same quality standards. If you wanted to get really picky about it you should choose a mined, non-brine, non-processed, non-refined salt produced at a facility that follows modern standards. The easiest to identify would be "himalayan" salt, but many countries have ancient lake/sea beds and mine and produce salt in the same way. In general, you can't tell how salt was produced unless the company very explicitly tells you. Even kosher and sea salt sometimes is processed or refined with additives or in a way that could introduce MPs. (In case it helps, only some places like Australia and the mediterranean have the right environment to solar-evaporate sea salt at a commercial scale)