Rotten-Egg Smell Due to Refinery Problem

A malfunction at the Citgo refinery in Lemont is responsible for the sulfur, rotten-egg smell permeating the southwest suburbs early this morning, according to local authorities.

Citgo officials told local police an equipment issue is to blame. The odor could be detected in Lemont, Darien, Woodridge, Downers Grove, Romeoville and other nearby communities starting at about 3 a.m. Wednesday.

The refinery experienced small-volume flaring due to the shutdown of a flare gas recovery compressor at approximately 12:40 a.m. on Wednesday, according to a statement from Citgo.

“Normally, there is no flaring at the refinery. However, by design, when the gas recovery compressor shuts down, a small amount of gas is diverted to the flare stack, which combusts gas to safe levels. The flare was operating normally and the gas in the flare was combusted. There was no process upset or safety issue.”

Heavy fog this morning caused the odors normally released higher into the air to hang lower.

CITGO is conducting an investigation to determine the cause of the compressor shutdown.