Seems there was a hulaballo about erionite used in gravel roads in North Dakota a few months ago causing clouds of erionite traffic dust to be formed. I dont think people were aware of the dangers of erionite until relatively recently, probably thought it was just ordinary gravel dust.
Could be a problem that increases as States allow roads to go into disrepair and eventually revert to gravel roads due to financial costs of relaying roads.
https://www.sciencedaily.com/releases...0725162527.htm
https://en.wikipedia.org/wiki/Erionite
Health Concerns Grow Over Little-known Mineral
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