The U.S. Department of Health and Human Services has issued an ATSDR report on February 24, 2010 due to complaints from residents in neighborhoods in Hartford, Illinois about excess gas odors in the air. After testing air and ground samples, the neighborhoods were deemed to have an urgent health hazard with high levels of various hydrocarbons including Benzene. Benzene and its derivatives are linked to certain types of leukemia. Residents were offered alternative lodging until the conditions were resolved.

The ATSDR report does not identify the cause of the petroleum vapor intrusion. However, Hartford, Illinois has had a decades-long history of having an underground petroleum plume that was linked to Apex Oil Company. In fact, according to the USDOJ, after a 5-week trial, Apex Oil was ordered to clean up Hartford with an estimated cost of $150 million to $300 million.