Prince George's County fire officials said yesterday the believe that a malfunction in an air conditioner caused an early morning explosion yesterday that seriously injured a Chinese student and hurt another at the University of Maryland.

The student was listed yesterday in critical condition at Prince George's General Hospital with injuries from the explosion that hurt another Chinese student and caused $60,000 to the College Park municipal building.

Lhosital officials said Cuo Ren Wu, 40, who was walking by the building with three other students, suffered extensive brain damage.

The other injured student from the People's Republic of China, Ben-Qi Guo, 37, was treated for abdominal injuries and released from the hospital yesterday afternoon.

The other two students who were also walking by the building at the time of the 12:18 a.m. explosion were not treated for injuries at the hospital and it is not known if they were hurt. Their names were not released by fire authorities.

Fire Department officials said there was no fire at the building at 4500 Knox Rd. where the explosion blew a "substantial hole" in the roof of the brick building and shattered windows in the building and nearby structures. The cause of the explosion was being investigated by a county bomb squad, but a spokesman said investigators believe that it may have resulted from an air-conditioner malfunction.