Between 1980 and 2015, Mexican immigration to the United States and the share of Mexican immigrants in the labor force quintupled. We provide the first evidence examining whether this impacted one element of the work environment for native workers: workplace safety. To account for endogeneity and ensure that the change in Mexican immigration arose from supply shifts, we use 2SLS and instrumental variables. We show Mexican immigration over this period led natives to work in safer jobs; resulted in fewer workplace injuries for natives; and reduced WC benefit claims overall, which had a meaningful impact on employer costs for WC.