For most of July 2019, stifling heat hung over the agricultural fields of California’s Central Valley, as farmworkers like William Salas Jiminez labored under the sun’s searing rays. Temperatures had dipped from 99 to 95 degrees Fahrenheit the last day of the month, when the 56-year-old Puerto Rico native was installing irrigation tubing in an almond orchard near Arvin, at the valley’s southern edge.