"Centerbeam," the multimedia per forming sculpture set up on the Mall last week, had its dramatic lasers shut down by the Food and Drug Administration Sunday for violation of government safety standards, but expects to have them on again by early next week.

"Their lasers are not yet calibrated to be used safely," said Joanne Long of the FDA's Bureau of Radiological Health, which last week warned the Blue Oyster Cult against careless use of the powerful lasers in their rock shows.

"'Centerbeam' is using class-4 lasers, a hazardous category that could cause permanent damage if one of the beams should wander and hit the retina of the eye," Long said.

"I understand FDA's responsibility, and I respect it," said Paul Earls, who is in charge of "Centerbeam's" lasers. He is now in Cambridge hastily fabricating an aperture that it is hoped will satisfy FDA's safety standards.

When "Centerbeam," the creation of 21 artists from the Center for Advanced Visual Studies at M.L.T., opened last Thursday night, FDA officials were on hand and observed that the beam was not adequately secured.

"We always knew the beam would have to be shielded after we got proper alignment," said Earls. "We're drawing laser images, you know, not just sending a beam, and the whole image has to sit on the Air and Space Museum wall."

So with FCA officials standing nearby, the M.I.T. artists and technicians began aligning the lasers and focusing the beams so that the components could be permanently fixed, which the FDA said would satisfy their safety requirements.

Earls subsequentlely left for Cambridge to build an aperture "which will insure that the beam and other laser projections can go no place other than where they're supposed to go, which is in the side of the Air and Space Museum."

"The culprit here was the water," said Bill Cadogan, project engineer. "We couldn't focus the lasers until we had water to cool them. But they couldn't find the water main, and then they couldn't find the valve. We finally had to hook up a hose to a fire hydrant, but by then we were 10 days behind schedule.

"Everything will be in place by Friday, and then we just need FDA approval to go ahead. I suggest people wait until the laser is back in action before they come down."

"Centerbeam" will be on view through Labor Day. In addition to the lasers, it involves many technologies, old and new, from steam and a giant prism to neon-argon beams, holograms with solar trackers, and a giant "kalliroscope."