WEST BRANCH — The Department of Environmental Quality’s Air Quality Division said an ongoing odor situation at the MichCon DTE Odorant Station in West Branch is improving, although a direct source has not been found yet.

Air Quality Division Environmental Quality Analyst Sharon LeBlanc told the Herald on Oct. 15 that the Air Quality Division was put in charge of an initial complaint filed against the company for overly strong odors in the springtime. She said the division, upon its first field visit, issued a violation warning and has been working with both DTE and the person who filed the complaint to spearhead the odor problem.

“We’re still solving the problem … (the odor) volatilizes very well,” she said, adding the division’s headquarters are an hour away making it difficult for them to track the main source of the smell.

According to both LeBlanc and DEQ Office of Geological Survey Senior Geologist Ray Vugrinovich, the odor could be a number of things including hydrogen sulfide or mercaptan.

LeBlanc said mercaptan, which has such a strong smell it can be noticeable at one part per billion, is typically added to natural gas to make it possible to find leaks in natural gas pipes.

“For mercaptan to be considered a dangerous level, you wouldn’t even be able to stand the smell,” LeBlanc said. “It would stink so bad you couldn’t handle to be around it.”

Hydrogen sulfide is a natural chemical in the Earth found in natural gas, which has to be extracted during the purification process, said Vugrinovich. He said at 300 parts per million, the DEQ considers hydrogen sulfide dangerous to the human body, and at 50 parts per million down to parts per billion it only carries a terrible egg-like smell.

“We’ve taken a portable metering test out there for hydrogen sulfide but we couldn’t find a (direct source),” he said.

“We don’t know why hydrogen sulfide occurs,” he added. “Investigating the odors (at DTE) is difficult to track because by the time we get out there, they’ve (diminished).”

Vugrinovich said the DEQ has performed a few tests at the site; however, it wasn’t able to find a direct source for the reported foul smells.

He went on to say there haven’t been any large-scale studies on the effects of long-term low-level exposure to hydrogen sulfide.

However, many reports online, including the Australian government’s Department of Environment, Water, Heritage and Arts Web site’s Hydrogen Sulfide Fact Sheet, http://www.npi.gov.au/

database/substance-info/profiles/49.html, say concentrations of 100 to 200 parts per million over one to eight hours can result in sleeplessness, blurred vision, hemorrhage and death while lower concentrations can result in a variety of complications.

“Lower concentrations may irritate the eyes, nose and throat (5 to 50 parts per million),” it says. “Following an exposure there may be headaches, dizziness, and nausea. Repeated exposures may cause headaches, anorexia, insomnia, paralysis, meningitis, psychic troubles, slowed heart rate, bronchitis and a grey-green line on the gums.”

LeBlanc said that she asked the person who filed the complaint to follow up with her by calling her whenever there is a smell and to take notes of the weather factors, such as wind direction, to give them a better idea of where it is coming from.

“We’ve been very progressive, and we’ve seen a significant decrease,” she said. “We’re continuing to monitor the situation.

“If anyone suspects a foul gas odor believed to be dangerous, they should contact the DEQs PEAS database online at www.michigan.gov or at 1-800-662-9278,” she said. ?