HILO, Hawai'i — School was canceled for about 1,300 Big Island students yesterday after an early-morning fire of suspicious origin did an estimated $1.5 million in damage to Waiakea High School's administration building.

Fire officials had not yet determined the cause of the blaze, but the fire was the third on campus in eight weeks.

The previous two fires damaged portable classrooms on the Hilo campus, and fire investigators suspect both were deliberately set. There were no arrests in those fires.

Yesterday's blaze apparently started in the registrar's office and was far more destructive.

The blaze caused extensive fire, smoke and water damage to the health room and registrar's office as well as areas used by counselors, special-education staff, the principal and vice principal, school complex area superintendent Valerie Takata said.

The school will remain closed today, and no classes are scheduled for the rest of the week because of a teacher training day tomorrow and the Good Friday holiday, Takata said.

Waiakea principal Patricia Nekoba said school staff were working yesterday to move offices elsewhere on campus, and said Waiakea will reopen Monday.

She said records were salvaged, but that the fire damaged the nerve center of the school.

"All the trunk lines, electrical, computer networking, telephone lines, they all run through the admin office, so at this point we're just waiting to see what the extent of the damage is and how fast we can get that up," she said.

Nekoba said a breezeway that separates the school offices in Building A from other school facilities kept the fire from spreading farther.

"We were lucky the fire didn't go that way," she said.

Takata said the blaze was reported by a neighbor at about 1:07 a.m. yesterday, and fire officials reported the administration office was engulfed in flames that were spreading to the roof when fire crews arrived.

Pipes burst in the ceiling, causing additional water damage before the fire was extinguished at about 4:30 a.m., fire officials said. Offices for about 20 staff people in seven or eight rooms were damaged, Takata said.

County Civil Defense officials issued an advisory to students to stay home, but teachers and staff reported for work yesterday to plan how to respond to the setback.

"At a time where something like this happens, it's always a tragedy and a loss for a school of this size, but the school team that responded here when I came at about 2:30 or 3 o'clock, they were on it, and that said a lot about spirit at the school. They're resilient," Takata said.

"The building is a building, but it's the school spirit that burns stronger, and we'll overcome this."

Big Island Assistant Fire Chief Quince Mento said authorities aren't certain yet whether yesterday's fire in the administration building was deliberately set, but investigators suspect two other fires on campus earlier this month probably were arson.

Mento said there were signs that a flammable liquid was spread along some doors that were burned in Building 20 at the school on April 5. That fire, at about 9:40 p.m., did an estimated $2,500 damage, and had been extinguished by the time firefighters arrived, Mento said.

Investigators also suspect a fire at 10:30 p.m. on Feb. 15 at another portable building was deliberately set. That fire singed a wall and part of a walkway railing, doing an estimated $500 damage.

The school also suffered major damage on Aug 20, 2002, when an early-morning fire burned part of a two-story, 10-classroom building. That fire started in a storage shed next to a concrete-block structure known as Building R, destroying two classrooms and causing an estimated $400,000 damage.

Big Island police took over the investigation of yesterday's fire, appealing to the public for help in determining who or what caused the blaze.

"Incidents like these hurt not only the school but also the students and the community as a whole," said police Capt. Chadwick Fukui in a written statement.

Anyone with information about the fire is asked to call detective Tom Poy at 961-2383 or the police nonemergency number at 935-3311.

Tipsters who prefer anonymity may call CrimeStoppers at 961-8300 in Hilo or 329-8181 in Kona. All CrimeStoppers information is kept strictly confidential.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.