Elk Grove Village police and firefighter/paramedics responded about 8:46 p.m. Monday to a report of a strong smell of natural gas just north of the intersection of Arlington Heights Road and Higgin Road. Firefighters discovered that NICOR was “blowing down” a main gas line near the intersection of Cosman and Winston in Elk Grove Village.
Operators of natural gas pipeline systems routinely reduce line pressure and discharge gas from pipeline sections to ensure safe working conditions during maintenance and repair activities. Typically, operators block the smallest possible linear section of the pipeline and depressurize it by venting gas to the atmosphere.
— EPA.gov [Using Pipeline Pump-Down Techniques To Lower Gas Line Pressure Before Maintenance (PDF)]
Arlington Heights firefighter/paramedics responded about 9:03 p.m. to a strong odor of natural gas in the 2400 block of South Goebbert Road at the Brittany Place Condominiums.
Mount Prospect firefighter/paramedics responded about 9:12 p.m. to the 400 block of South Maple Street to a report of natural gas odor .
Mount Prospect firefighter/paramedics also responded about 9:19 p.m. to the 700 block of Dresser Drive to a natural gas odor.
Mount Prospect firefighter/paramedics also responded about 9:30 p.m. to the 600 block of South St. Cecelia Drive to a natural gas odor.
Mount Prospect firefighter/paramedics also responded about 9:30 p.m. to the 300 block of North Russell Street.
Firefighters detected some readings in the sewer that were apparently caused by dryness and lack of rain. No word on the gas that was detected.
No hazardous gas levels were detected by any fire departments in the area. It is not confirmed whether the odor in Mount Prospect was from the natural gas blowdown in Elk Grove Village or from hydrogen sulfide emanating from dry sewers.
In November 2010 after a dry weather period, hydrogen sulfide gas was discovered emanating from deep tunnel lines and feeder drainage lines. Arlington Heights police, firefighters and public works officials responded to multiple odor investigations in the area surrounding Euclid Avenue and Arlington Heights Road and southeast toward Kensington Road and Gibbons. The odor was determined to be hydrogen sulfide gas that was escaping from the deep tunnel project tunnels caused by dry conditions and lack of rain during the 2010 fall season. Public works officials flushed water into the drainage pipes to remedy the emanating Hydrogen sulfide gas.
Hydrogen sulfide is a poisonous, flammable gas with the foul odor of rotten eggs. Hydrogen sulfide is a different gas than natural gas, which is principally the odorless and highly flammable methane gas. An odorant (tert-Butylthiol or t-butyl mercaptan or thiophane) is added to natural gas, so that dangerous natural gas leaks can be detected. According to a Pipe & Gas Journal article (The birth of green is good for Nicor), Nicor Gas uses mercaptan.
See also …
The Cardinal Flushing with Fire Hydrant Water: Natural Gas Smell Reported Is Likely Hydrogen Sulfide Odor from Dry Deep Tunnel
The Cardinal Deep Tunnel Gas Odor Reports Continue, This Time Near Mariano’s, Kensington & Dryden