About 125 farm workers were treated at a medical center in Yerington when they were sickened by a chemical used on an adjacent field.
Lyon County authorities say the workers began feeling ill shortly after 8 a.m. while working in an onion field owned by Peri & Sons, Inc.
The company farms about 1,800 acres in the Mason Valley around
Emergency manager Jeff Page says a nearby field had been treated on Monday with chloropicrin, a fumigant used for agricultural pest and fungus control.
It also was used as a chemical warfare agent during World War I.
Page says the chemical gives off gases that generally blow away, but an inversion early this morning kept the fumes near the ground, where workers inhaled it.
No one was seriously injured.
State occupational safety officials were investigating.