Human skeleton found in underground vault at shut down Blue Island oil refinery

A contractor stumbled upon human skeletal remains Thursday in an underground vault at an oil refinery that’s been closed for almost 20 years in unincorporated Blue Island.

The contractor opened an underground electrical vault at an industrial site about 9:25 a.m. in the 3100 block of West 131st Street and found the remains, according to the Cook County sheriff’s office.

The remains belonged to an adult in blue jeans and gym shoes, the sheriff’s office said. The remains were taken to the Cook County medical examiner’s office, which scheduled an autopsy for Friday.

The sheriff’s office said the death remains under investigation, and that there were no signs of foul play.

The medical examiner’s office said the remains were found at 3133 131st Pl.

That’s the site of a former Premcor Inc. oil refinery, which shut down in 2001 after operating there since 1945. The refinery had been cited for environmental and safety violations.

A spokesman for the sheriff’s office could not comment Friday on how long the remains might have been at the site, whether it appeared the man was locked inside or who owned the vault.