ALTADENA, Calif. — For months, the day laborers had decontaminated homes that survived the Los Angeles wildfires. Sweating in masks and protective suits, they vacuumed toxic soot and ash, wiped down books and framed photos, and disposed of clothes and furniture that could not be salvaged.

Immigration enforcement operations on farms have left crops rotting and farm operations disrupted in major agricultural states including California, Texas, and Pennsylvania.