A backed up internal wastewater line that resulted in foul odors and water seepage in a couple of rooms prompted school administrators to close Toll Gate High School yesterday shortly after noon.

News of the early dismissal was disseminated over the connect-ed system and by the local news media. The incident also prompted the relocation of last night’s honors night from the Robert J. Shapiro Cultural Arts Center to the nearby Winman School auditorium.

A backup of the system was detected Tuesday afternoon and identified as a blockage under the gymnasium floor, said Dennis Mullen, director of secondary schools.

“We called in private contractors to get to the bottom of this,” he said yesterday.

Apparently, a crew worked throughout most of the night, and the situation was believed to have been corrected by the time school opened Wednesday. That was until foul orders were detected in some of the bathrooms as well as wastewater in the art room and room 106 that are at the opposite side of the building.

“They’re putting down cameras [in the drainage system] and they’re looking for any blockage,” said Superintendent Richard D’Agostino.

While odors were not detected throughout the building and the blockage is likely to be isolated, D’Agostino said with the cafeteria he thought it best to close the building. D’Agostino believes the problem is based at the school and is not related to the sewer system.

“It’s frustrating,” he said, “they worked all night to correct it.”

As of Wednesday, the School Committee meeting planned for tonight at the school has not been relocated. That will be a closed session and no more than the five-member committee and attorney Vincent Ragosta, who has been investigating the school administration’s response to allegations about a Gorton science teacher, are expected to be in attendance. (See related story in today’s paper.)