LAWRENCEBURG, Tenn. -- Some Lawrence County parents said they are concerned about the safety of their children’s school.

Video: Mold In Portable Classrooms Concerns Parents

Parents said they are worried about a potential health hazard caused by mold in some of the county’s portable classrooms.

The portable classrooms were brought into use about 20 years ago as a temporary fix to relieve overcrowding.

Over time, water has seeped through cracks and caused some structural damage, and parents have been worried for some time about the possible existence of mold.

Underneath the wallpaper in at least one of the classrooms, Channel 4’s Catharyn Campbell found mold.

In 2007, school administrators said a massive cleanup was done but the mold is now worse than it was, officials said.

At South Lawrence Elementary, there are 12 portable units, five of which have tested positive for extreme levels of mold.

School officials said they want to shut the units down and a number of parents said their children have gotten sick from attending class in the portables.

"Absolutely they are unhealthy. I wouldn’t put an animal in them," said County Commissioner Chris Jackson.

One parent said her child was very sick.

"She was on five medications just to come to school. And during the spring break, when she was out of school, she got better, and as soon as she went back to school, it started again," said parent Kim McMasters.

In addition to the 12 units at South Lawrence, school officials said they want to dispose of nine other units at New Prospect Elementary.

Officials said they are hoping to use money from an increase in a wheel tax to make improvements to the schools.

A meeting was set with school administrators and parents for Monday night to discuss the schools’ problem.

A portable classroom distributor said the portable classroom buildings often need the roofs sealed every three to five years and that if leaks are not taken care of quickly, they can cause major problems.

The representative said it's not unusual for a portable to still be in use after 10 or 20 years if it hasn’t been moved around a lot.

Williamson County schools have two portable buildings that are 20 years old.