State toxicologist Rita Messing briefed Marshall County commissioners Tuesday about a preliminary report on a series of air quality tests at Excel Dairy.
The data shows that people living near the farm have been repeatedly exposed to elevated levels of hydrogen sulfide gas. Messing said the exposure is causing short-term health effects.
State law says hydrogen sulfide levels are supposed to be below 30 parts per billion outside the diary farm's property line. But Messing said levels as high as 480 parts per billion were recorded at nearby homes.
"That's a very high amount of hydrogen sulfide at somebody's house. Not at the fence line of the facility, but at somebody's house. And people need to make a judgement themselves whether they can stay or whether they should go. But at those levels, I believe that most people will suffer health effects," Messing said.
Short-term exposure to hydrogen sulfide can cause headaches, nausea and respiratory problems. Messing said the effects of long-term exposure are unclear.
"These repeated exposures are worrisome because we don't know what the effects of these repeated exposures might be, whether there could be some latent effects that aren't obvious now, that could be more serious," Messing said.
Excel Dairy said it's been unfairly characterized as a villain. Excel attorney Matt Forsgren doesn't dispute there's a foul odor around the dairy farm. But he said it got bad after the Minnesota Pollution Control Agency ordered Excel to make some changes to one of its manure basins.
Forsgren said the company questions the accuracy of air quality monitoring equipment used by state and federal investigators. And he questions what's actually considered a safe level of hydrogen sulfide exposure.
He said the safety levels used by federal and state agencies are too strict.
"We wanted people to know that the readings that have been taken can't be taken at face value, and that there are certain questions that need to be asked. And we finally want people to know that there aren't adverse health impacts as a result of the readings that have been taken," Forsgren said.
Some local residents are angry with Excel's characterization of the problem.
Mona Loe said there's no doubt she and her husband are getting sick from the gas. They live about 300 yards from the Excel property. Loe works out of her home office, and said there are days when the stench is unbearable.
"It's very stressful. If my husband has been out in it, the next day he's just exhausted and short of breath and can't really accomplish anything because he feels so awful. I get headaches and nauseous," Loe said.
Last June the Minnesota Health Department advised neighbors of the dairy farm to leave their homes. Despite ongoing air quality concerns, the Health Department now says it's up to individual residents to decide whether to stay or go.
Jeff Brouse lives 800 yards from the farm. He worries about his family.
"The last couple of weeks haven't been good. Two Fridays ago we had to leave our home. And it was so bad it invaded our home and it was very bad and we had to leave. No one should have to leave their home. My wife's four months pregnant. I've got a four and a six-year-old. It's unbelievable. It's like we live in a third world country," Brouse said.
Excel Dairy faces a criminal lawsuit filed by Marshall County. The company also faces a suit from the Minnesota Pollution Control Agency and the Attorney General's office.
An Excel spokesman said the company is cooperating with state agencies to find a solution to the problem.