VANCOUVER, Wash. -

Third-graders at a Washington elementary school have to pay with play money to use the bathroom, according to a CBS TV station.

The Evergreen School District in Vancouver is looking into claims that the "fake money" system is causing some third-graders to urinate in their pants.

Parents told KOIN-TV a third-grade teacher at Mill Plain Elementary School uses the play money as part of the curriculum. Students earn the play money each day in class and use it on toys, popcorn, pizza and other treats. However, students told KOIN-TV they must also use the money to go to the bathroom.

"Nobody should have to pay to use the bathroom," Merchon Ortega, a parent, told KOIN-TV.

Ortega said her daughter chose to spend her play money on treats instead of the bathroom, leading to an accident during class.

Jasmine Alayadhi told KOIN-TV her daughter made a similar choice and ultimately wet her pants as well. Alayadhi's daughter told her parents she wanted to "have popcorn with her friends" and tried to "hold it."

"She said it hurt so bad and the pain was so bad," Alayadhi told KOIN-TV. "They have to do something. It's inhumane. It's sickening."

Gail Spolar, a spokeswoman for Evergreen School District, said the district decided to allow the play money curriculum because it was how the teacher planned to "manage the classroom."

Spolar said students are allowed to have bathroom breaks during the day, but it is up to each teacher to decide how to manage those breaks. The district maintains no students are denied the right to use the bathroom.

The teacher who used the play money system will not be allowed to work during the district's investigation.