The principal of St. John the Baptist school, Sue Clausen, says the problem started when a school worker found a box of science equipment in the garage. The worker took it to a teacher, who told the worker to get rid of it.
The box contained a vial of mercury, which spilled in the cafeteria, a nearby hallway and a science lab. Clausen says a teacher saw the mercury on the floor, but not before some students had walked through the contaminated areas. Clausen asked students to turn in their shoes for testing.
"It was around bus-boarding time that I ended up having to kind of catch them before they left on the buses and get their backpacks, because I realized they had put their shoes in there, and that's what had been tracked around the school," Clausen says.
Mercury was discovered on some shoes, including Clausen's. While she wasn't happy to have to get rid of what she describes as a "pretty cute" pair of shoes, she isn't worried that her health was compromised.
"I am completely assured from the Department of Health that there is no way that I need to worry, or that I need to worry about my staff, or my students or the parents," says Clausen.
Four hundred students in grades kindergarten through eight attend St. John the Baptist school.
Mercury can damage the central nervous system, kidneys and liver. It poses the greatest risk when inhaled as a vapor. State officials say the amount that was spilled at the school was relatively small, probably a couple of spoonfuls.
Department of Health toxicologist Carl Herbrandson says unless students were playing with the mercury, or poured it onto their scarves and wrapped them around their heads, students would not have been exposed to dangerous levels of mercury.
"The feedback that we've had on this, from everybody from the principal on down, is that there have not been extraordinary exposures -- that in fact, they have controlled it, they controlled it pretty early on," Herbrandson says.
Herbrandson was also on the scene of last year's mercury spill at a school in the Eden Valley-Watkins district. He says schools often run into problems when they're trying to remove hazardous materials.
“They were so on it that I never had a chance to get scared.”Parent Jane Heinks
"Unfortunately, it seems to happen sometimes when schools decide they're going to get rid of the equipment, that they're not careful in how they're doing this."
Herbrandson advises schools and homeowners to get rid of mercury thermometers and thermostats by triple-bagging them in plastic -- not putting them in a box -- and taking them to a hazardous waste facility.
Herbrandson and officials with the Minnesota Pollution Control Agency met with students and parents the day after the spill to answer their questions. Jane Heinks, who has two children at St. John the Baptist school, says she's impressed with the school's quick response.
"They were so on it that I never had a chance to get scared," says Heinks. "It was just, 'This is what we're going to do, this is what we're worried about, this is how we're going to take care of it, and your children are our utmost concern.'"
Heinks says she only wishes the students would have been told exactly what the problem was, since they didn't know what to think when they were asked to turn in their backpacks. Her son Henry, a first grader at the school, says students had all sorts of ideas.
"My friend I was sitting with, who was right next to me in line, said maybe they were checking for nuclear bombs. And a sixth grader told him that someone had a gun in their backpack," Henry says.
Principal Sue Clausen says she didn't want to scare students about the mercury spill. She says the bright side of the whole situation is that kids get an unexpected break from school.
"We have happy kids, because no homework, no tests. Not often do they hear that from their principal."
Clausen says she's not sure what the school will end up paying to clean up the mercury spill. In Eden Valley-Watkins, the cleaning bill was $126,000, and the district is hoping the Legislature will help with the cost.