Wantagh High School students have to carry their books and belongings in clear plastic bags and are locked out of their lockers for the rest of the school year following a rash of threats, school officials said.
The safety measures, which include new security cameras and a ban on backpacks and large bags, started Tuesday, according to schools Superintendent Maureen Goldberg's May 22 letter on the school's website.
The rules are part of the precautions that began on Friday, when students were instructed to clean out their lockers, which then were sealed for the rest of the school year. The students' plastic bags also will be checked.
The regimen was put in place after "yet another message" prompted school officials to call the Nassau County Police Department, Goldberg said in her Web posting.
"The police immediately responded, searched the high school and determined it was safe to conduct normal after-school and evening activities," she said.
The superintendent added: "This is a very serious situation that requires that further measures be taken."
Goldberg did not say when the latest message was received.
The policy may be "drastic" in some ways, but school district officials are between a "rock and a hard place," said Robert English, 47, whose son Nicholas, 18, is a high school senior.
"I think it's a little extreme," the father said, "but I don't mind it because if something were to happen, I'd hold them liable. I'd be down there screaming."
There have been several threats involving "messaging that included the threat of a bomb," a school spokeswoman said.
Nassau County police said that on May 1 the school's principal "was notified by students of a specific threat written in a men's bathroom on the first floor."
The high school and adjacent middle school were evacuated as a precaution, and students were later allowed to return.
The school is easing one of its earlier restrictions: It will open a second set of boys and girls bathrooms that will be monitored.
All but one of the bathrooms for each gender had been shut and students had to sign in and sign out. The school district since has taken other security measures, the spokeswoman said.
"Additional interior cameras have been installed within the building as well as security personnel placed in the high school," she said.
With Ellen Yan