Residents of about 20 houses in South Superior were warned not to enter their homes Thursday afternoon after the Fire Department found dangerous levels of hydrogen sulfide in one of the houses.
The emergency is directly related to the industrial accident that took four lives in the same area last week, Mayor Dave Ross said.
The houses in the 6300 block of Banks Avenue were tagged to warn residents not to enter until the homes could be tested, he said. Most of those homes had been tested as of 8:30 p.m. and residents were allowed to return to their homes, except the house where city officials found levels of hydrogen sulfide at 140 parts per million.
Ross characterized the readings as "significant."
According to the Centers for Disease Control, Exposure to low concentrations of hydrogen sulfide may cause irritation to the eyes, nose, or throat. It may also cause difficulty in breathing for some asthmatics. Brief exposures to high concentrations of hydrogen sulfide (greater than 500 ppm) can cause a loss of consciousness and possibly death. In most cases, the person appears to regain consciousness without any other effects. However, in many individuals, there may be permanent or long-term effects such as headaches, poor attention span, poor memory, and poor motor function.
ADVERTISEMENT
The Occupational Safety and Health Administration limits exposure to hydrogen sulfide at 20 ppm for a maximum of 10 minutes with a ceiling limit of 50 ppm. OSHA is considering new rules to cut that limit in half.
Hydrogen sulfide occurs naturally in crude petroleum, natural gas, volcanic gases, and hot springs. It can also result from bacterial breakdown of organic matter, such as decomposition in a landfill.
The house at 6325 Banks Ave., where the problem was reported, appeared to have a problem such as a dry trap or floor drains that allowed the gas to enter the home through the sewer system and will have to be checked out by a plumber, Ross said Thursday night. Hydrogen sulfide was not found in the other homes, he said.
The gas appeared to have been pushed into the sewers in the area when a blocked pump was turned back on today at the Lakehead Blacktop and Materials of Superior Inc.
The pump at Lakehead Blacktop and Materials was turned off immediately after the high levels of gas were detected, and readings for hydrogen sulfide gas were at zero at six manholes in the area by 4:30 p.m., Ross said.
In addition to warning residents not to enter, firefighters flushed and diluted the sewer system in the area, Ross said.
Firefighters equipped with breathing apparatus put notices on the front door knobs of 20 homes. They read: "Attention: There has been hydrogen sulfide gas detected in your sewer line. Please don't enter your house until it has been checked for the presence of the gas. Please call the Environmental Services Division of Public Works at 394-0392."
Ross said most, if not all, of those homes were tested and found to be problem free.
ADVERTISEMENT
Area residents arriving home this afternoon spoke briefly to emergency workers and then drove away.
Lakehead Blacktop is owned by J. Kimmes Construction. Two members of the Kimmes family, Joseph Kimmes III and his brother, Scott Kimmes, both of Superior, died, as did Paul Cossalter of Wrenshall and Harold "Tim" Olsen Jr. of Foxboro.
Hydrogen sulfide gas is poisonous, flammable and colorless and gives off a strong odor of rotten eggs, according to the Centers for Disease Control.
"That smell has been going on and off ... I'd say a month or two," said Barb Miller, who lives in the 6300 block of Banks Avenue. She and her husband have noticed the rotten-egg smell two or three times a week. Until today she thought the smell was coming from the nearby refinery.
A Superior police squad car, a fire truck and a public works crew were called to the Banks Avenue home shortly after 3 p.m. today by workers from Belknap Plumbing and Heating after the company responded to a call from a concerned resident.
Among those responding on behalf of the city were Ross and Jeff Vito, director of development and government affairs. Ross said he was happy with the "aggressive response."
