Someone called Fife Police to report a suspicious vehicle in a parking lot in the 2500 block of 62nd Ave. East. about 10 a.m. Friday.
The person told police an unresponsive man was inside with a note taped to the window stating, "Do Not Open, Hydrogen Sulfide - Call 911.".
Hydrogen sulfide is a colorless, flammable, extremely hazardous gas with a rotten egg smell, according to the Occupational Health and Safety Administration.
Police arrived and immediately cordoned off the area.
The Tacoma Fire Department and Tacoma's hazmat team also responded, went into the vehicle and found the man dead.
The potential area of exposure "was contained and minimal," police said.
Police have not said what caused the man's death or if the gas was in fact present.
The area around 62nd Ave East is currently closed with police and fire officials on the scene but outside the contained area is safe, poilce said.