The U.S. Postal Service faces nearly $150,000 in fines following the heat-related death of a mail carrier in Southern California.

USPS was cited for a repeated violation of the federal Occupational Safety and Health Act’s General Duty Clause. The citations, which come with $149,664 in total proposed penalties, stem from an investigation into the death of a worker in Woodland Hills.

The general duty violation “addresses USPS’s programs and procedures for employees working in high-heat situations,” according to the U.S....