HAMMOND, Ind. (AP) _ Carbon monoxide fumes from an apparently faulty elementary school furnace sent about 150 children and teachers to hospitals Monday, but only one worker was admitted for treatment in a hyperbaric chamber.

Police received a call at 9:20 a.m. that ''kids were passing out at their desks,'' and between six and 10 children were unconscious when the Edison School was evacuated 10 minutes later, said police Sgt. Ron Hill.

''I just felt light-headed and nauseated,'' said Jill Dodge, a first-grade teacher. ''I think it hit us all at the same time.''

It was one of two mass carbon monoxide poisonings at schools resuming classes following the holiday break.

In Walnut Grove, Ala., 28 high school students and a teacher were taken to hospitals Monday after the gas escaped from a boiler, apparently through a faulty pipe connection, officials said. Ten people were admitted for observation.

All but one of the 148 people treated at six Hammond-area hospitals was released by Monday afternoon.

Joan Nightingale, 55, of Hammond, was listed in good condition but was expected to be hospitalized overnight for observation at St. James Hospital in Chicago Heights, said hospital spokeswoman Lisa Lagger.

Ms. Nightingale, a school cafeteria worker, underwent treatment for carbon monoxide inhalation in the hospital's pressurized, oxygenated hyperbaric chamber, Ms. Lagger said.

It was the first day back for Edison's 426 students following their two- week holiday vacations.

City buses, churches and neighboring homes were pressed into service to help keep the children warm after they were evacuated, Hill said.

''I just happened to be here looking for my kid and had a station wagon. Now I have about 16 kids in there,'' said parent Debbie Evans.

Police said preliminary evidence indicated a faulty furnace was responsible for the leak, but authorities continued to investigate Monday night.

School Superintendent David Dickson said a fire department squad was to check the building early Tuesday, and he did not immediately know if classes would be held.

Fire Department Capt. Tom Pyplatz said the school building had been aired out before an initial measure showed carbon monoxide levels at 90-100 parts per million. Pyplatz said federal work place standards set 50 ppm as the maximum level for safe working conditions.

The highest concentration in the school may have reached 1,000 ppm before teachers began opening doors and windows, he said, adding that health and life become endangered at a level of 1,500 ppm.

Walnut Grove Police Chief Joe Hamby said seventh- and eighth-grade students at West End High School began ''dropping like flies'' in a home economics class. Officials said the fumes caused light-headedness, dizziness, nausea and some vomiting.

The students and their teacher were led out of the building and emergency medical technicians administered oxygen. Ten students were admitted to a hospital for observation.

School Superintendent Ralph Cain said the fumes came from a large smokestack-type pipe that was not properly reconnected after a new roof was put on the building housing the cafeteria and home economics department.

He said the fumes did not spread to other buildings.

The duct was later connected properly and classes were to be held as usual Tuesday, he said.