MONROE, Wash. – Several classrooms and other spaces are closed at a Monroe school after a test in December showed high levels of PCBs.

Sky Valley Education Center has had issues with PCBs, or polychlorinated biphenyls, in the past. According to school documents, last year higher than acceptable levels of PCBs were found in several locations around the school. The source of the PCBs is unclear, but district officials suspect the light bulbs and caulking could have been to blame.

In an effort to remove all PCBs from the school, this summer the district renovated the building. According to Superintendent Dr. Fredrika Smith, the district spent $1.2 million to rid the school of PCBs and renovate the HVAC system.

"Because we have done very thorough testing and a lot of renovations, and there's nothing to indicate that we shouldn't have kids in this school," said Smith. "If there was any concern about health, we would not be using it as a school."

Smith said several tests done after the renovations detected no PCBs. However, in December a test came back positive for seven spaces around the school including a classroom, locker room, and a gym.

The school district says they and the environmental group that did the test believe the test was an "anomaly." This is mainly because no other tests showed signs of PCBs, and the control group in the test also came back positive for PCBs.

To be safe, the Monroe School District tested those same areas again in January. This time, no PCBs were detected. But taking even further precautions, Wednesday the Monroe School District decided to close the seven spaces that initially tested positive for PCBs. A letter was sent home to parents. Students affected are being relocated to other spaces.

Additional testing on the rooms will be done this week. The district says the spaces could open as early as next Friday.

850 students attend Sky Valley Education Center, an alternative school. The school primarily provides additional education for those in the area who are home-schooled.

The school was built in 1968. The federal government didn't stop production of products with PCBs until 1977, so it's not a surprise to find PCBs in an older and school like Sky Valley.

The issue for a group of parents and teachers, the Healthy Sky Valley Advocacy Group, is the way the school is handling the situation. The group claims dozens of students, parents, and teachers reported symptoms, such as headaches and nosebleeds. They attribute the symptoms to PCB exposure and started a petition to urge the school to move buildings to avoid any more health impacts.

The Monroe School District says the symptoms aren't linked to PCB exposure, rather issues with the school's HVAC system before it was renovated this summer.

"As a Mom and a Grandma, I take that very seriously, and when I say that the health and well-being of our families and staff are of the highest importance, we would never take a chance and put people in an environment that wasn't safe," said Smith.

The Monroe School District says they have a plan in place to test areas of the school for the next two years. Smith says relocating is not an option.

"To find a facility that would house this big a program, there isn't anything like that in the area," said Smith. "This is really the best location to have a comprehensive education available to the kids that are here."