Every morning that Ronald Barrett runs the long stretch of sidewalk along Anascostia Avenue NE headed to his fifth grade class at Nevel Thomas Elementary School, he wonders whether it will be the day someone blows up his school. "Sometimes," he says, "I'm afraid that the building is going to blow up into a billion tiny pieces right before I get inside and I'll be the only survivor."

Since late February, Barrett, his 564 classmates and their teacher have had to evacuate the school building approximately 20 times, sometimes remaining outside for as long as three hours, without coats, regardless of the weather, while police and specially trained dogs searched the building.

Aside from the psychological effects of the scares, Thomas Principal Sehon Grigsby said the frequent evacuation from the warm building into weather that is often inclement without time to put on sweaters, jackets and overcoats has caused health problems. "Teachers and students have been falling like flies with flu and colds and rheumatism," she said. "Some of our teachers are expecting, so they have really been endangered."

Grigsby and her staff at first tried to hide the truth of the bomb scares from the students by telling them that the school was holding special fire drill exercises to sharpen their emergency preparedness. But the children soon found out what was really going on. "One of the students probably overheard some teachers talking about the bomb threats in the hall," the principal said, "and then went to the cafeteria and playground to spread the news to the other students." Grigsby, a 26-year veteran in the D.C. public schools, has been at Thomas for the past two.

Barrett remembered that on the first day the fire alarm rang after the truth about the bomb threats had circulated among the students, he and his pre-kindergarten through sixth-grade schoolmates "thought the school was really going to blow up." He recalls that "it was real, real cold and everybody was shaking all over. I didn't think I was going to be able to get into my house because we left class so fast, I forgot my keys. I was real scared that day."

Grigsby said most of the threats have occurred in the mornings, right after the school bell rings to begin classes at 9 o'clock. Some have come right after lunch. Grigsby says that she has sent the students home for the remainder of the day about five times, usually when a caller has threatened to blow up the school twice in the same day.

"One or two parents who live within a block from Thomas come out to get their children and go home when there's a bomb threat," Grigsby said."They can hear the bell from where they live."

For many of the students, the fear of a bomb explosion is intensified because of the unsolved child murders in Atlanta. Some Thomas students believe that whoever is responsible for the Atlanta murders may have come to D.C. to threaten their lives as well.

"When we have bomb threats, sometimes I think of the murders in Atlanta," 11-year-old fifth grader Debra Saunders said. "Someone might be after us, too.

"Everybody was scared when we first found out what was happening. Everybody was shivering and stuff, but nobody said much. We just looked at the school and waited for the police to say we could go back inside." l

Claudette Jones, whose two sons attend Thomas, said the experience has been unnerving. "These bomb threats really make a mother nervous. It hurts," Jones said. " Why would someone threaten to hurt our children?"

"The baby (Donzarie, 4, in prekindergarten) doesn't really know the danger involved," Jones said. "The fourth grader (Eustice, 9) comes home and talks to me about it. He wants to know what would happen to him if a bomb did explode. He asks me why would someone try to do this to him. Then, he'll bring up the Atlanta children and ask me if someone is out to demolish the black race. I just tell him not to think about it."

Nevertheless, Bette Chase, a teacher who has worked at Thomas for 13 years, says, "The children here have adjusted to the threats quite well. They might joke about it sometimes, but they now realize that they are just as vulnerable as those children down in Atlanta."

Chase, other teachers and the school psychologist say none of the students has apparently suffered any long-lasting emotional stress as a result of the bomb scares. But, Chase says, "some of the students have had problems concentrating on their work -- some of them keep looking up at the clock to time the next bomb threat. But all the teachers have talked about the situation and none have noticed any serious problems in their classes."

Grisby said parents of Thomas students have cooperated with her and her staff in keeping the students from becoming preoccupied with the bomb scares. "The parents haven't panicked. We haven't had many of them keep their kids out of school and no child has been withdrawn. We've lost about two weeks of class time due to the evacuations, but the teachers and students have agreed to make up for that time by holding class during lunch time and recesses."

"We think we're dealing with the situation quite well, Grigsby said, adding, "that still doesn't diminish all of the frustration caused by the threats. When someone calls us and threatens to blow up our school, it's just so irritating. We hate to lose even five minutes of class time.

"We think that whoever's calling is just a prankster trying to disrupt the educational process, but still, we must treat every bomb scare as if it were a real danger."

"It's been more than two weeks now since we've had our last bomb threat," Grigsby said. "Usually we receive at least one a week. So," she concluded, crossing her fingers, "we think it's all over."