Father Judge High School will be closed Tuesday as city health and hazardous-materials investigators try to determine why about 150 people who attended a cheerleading competition Sunday night wound up seeking treatment for burning eyes.

The Archdiocese of Philadelphia ordered the Northeast school closed for the day as a precaution and canceled all activities, including an evening for prospective students that had been scheduled for Tuesday night.

James Garrow, a spokesman for the city Department of Public Health, said it was not initially apparent why people were turning up at hospitals early Monday morning complaining of eye problems.

But a common factor soon became clear, he said: All had attended the event at Father Judge, on Solly Avenue in the Holmesburg section of the Northeast.

About 1,000 people attended the cheerleading competition, held in the school's auditorium, according to archdiocesan spokesman Kenneth Gavin.

Garrow said patients started arriving at four hospitals in the Northeast about 2 a.m. Monday and continued to show up through the day.

As of 5:30 p.m. Monday, 155 people had reported symptoms at emergency rooms in Aria Health-Torresdale Campus, Aria Health-Frankford Campus, Nazareth Hospital, and Jeanes Hospital. Of those, nine patients were still in Aria-Torresdale's emergency room Monday evening, Garrow said.

Investigators had not determined what caused the people to suffer burning eyes, though Garrow said the condition did not appear to be life-threatening.

Garrow said that hazmat teams would conduct a series of standard tests Tuesday morning to determine the cause of the irritation.

The tests are designed to pick up airborne irritants such as ammonia, chemical agents, and volatile organic compounds, such as degreasers.

A contractor for the archdiocese will also test the school's cleaning agents, Garrow said.

"Everything seems to be isolated to this cheerleading competition," the archdiocese's Gavin said, adding that families of students who attend Father Judge were notified by e-mail, an automated telephone message, and a notice posted on the school's website.

Father Judge had notified the city Health Department about several reported cases of MRSA, a difficult-to-treat bacterial infection, at the school in mid-November, but Garrow said that city officials believe this event was unrelated.

The high school was closed Monday for an off-site teachers' in-service day.

The prospective-students night has been rescheduled for Jan. 17, and Garrow said no decision had been made Monday night on whether the all-boys school would open Wednesday.