A foul smell is causing problems at a northeast Iowa school — again. It was Thanksgiving a year ago when a sickening odor began to linger inside West Cedar Elementary School in Waverly. The smell got so bad, Waverly-Shell Rock District officials closed the building for two months last spring and relocated classes to other nearby facilities. Last summer, school officials spent 170-thousand dollars on construction, cleaning, and consultants in an attempt to clean the air. The smell dissipated, so the district reopened West Cedar in August. Now, the smell has resurfaced. Three teachers and 10 students are blaming recurring headaches and strained vocal cords on the lingering odor. District officials still don’t know what’s causing it. They hired another consulting firm to conduct more tests, but the results likely won’t be known for another week. District officials say the test results will determine if they’ll have to relocate classes from the school again.