A cooling unit that broke down during this summer's sweltering heat has sprouted a major mold headache for school officials in Jordan, where elementary students will get an extra week of vacation while workers scramble to clean up their school.

Students at Jordan Elementary will start classes on Sept. 12, nearly a week late, the school board of the Scott County district decided Wednesday night.

The delay will give workers more time to install new carpeting, clean air ducts and put furniture back in classrooms after mold was found in the building several weeks ago. A consultant whose company tested the school for mold contamination said Thursday that he believes the building is safe, but school officials say they're taking pains to make sure problems don't recur.

"We didn't want to be taking chances," Jordan Superintendent Kirk Nelson said.

The problem started several weeks ago, when one of the school's cooling units, or "chillers," failed during unusually hot, rainy weather, Nelson said. Humidity levels in the building shot up, creating a mold-friendly environment.

Mold was found on carpets in "quite a few classrooms" on the east side of the building, Principal Stacy DeCorsey said. Workers used a mold-killing solution on the carpets, and Industrial Hygiene Consulting (IHC) of St. Paul was hired to test the school's air quality, carpets and ducts.

Mold can be found almost everywhere, and it's impossible to eliminate it entirely in buildings, according to the Environmental Protection Agency. But employers and school officials take steps to prevent mold growth because exposure can trigger health issues for some people, especially those with allergies or respiratory problems.

Overall, tests showed that Jordan Elementary's air quality and building materials were "normal, typical and not problematic," IHC owner Slade Smith said. "There were a few areas that needed to be addressed, but in an area the size of an elementary school, that isn't that uncommon."

The company swabbed air ducts and found a couple with elevated levels of fungi or bacteria, he said. It also tested carpets samples and found one third-grade classroom with unacceptable mold levels, the company said in a report to the district this week. It recommended recleaning the carpet in that classroom and taking steps to lower the building's humidity level.

But district officials found that cleaning the carpeting, which is nearly 20 years old, would be so expensive that it made more sense to replace much of it, Nelson said. The school plans to recarpet several dozen classrooms, he said, adding that the old carpet lacked the "anti-mold stuff" in carpeting sold today.

The district is also installing a new chiller that should be in place by Sept. 1, said Don Horkey, a mechanical engineer with DLR Group who has been working with Jordan school officials. The new chiller will cost about $150,000, he said.

Cleaning the contaminated ducts will cost about $32,000, Horkey said. On Thursday afternoon, he said that he didn't know how much carpet installation would cost.

The district plans to send a letter to parents on Friday that will answer questions about the first day of school at Jordan Elementary. The start date for Jordan middle and high school students remains Sept. 6.

"I think they have it under control," said Jordan parent Dennis Schmit, who has four children and is also running for school board this fall. "I'm a little happier that they're waiting an extra week to get it cleaned up" rather than trying to start classes on schedule.

It's "extremely common" for schools to have mold problems, IHC's Smith said. "It happens every year. It happens all the time."

Asked how often students miss class as a result, he said, "It's all a matter of timing. If the school district doesn't catch it in time or the amount of the problem was large, like Jordan's apparently was, then it just takes time [to clean up]."

Sarah Lemagie • 952-882-9016