By MURRAY WEISS
June 12, 2007 -- The NYPD has stepped up its inspections of trucks at checkpoints to protect against radioactive, biological or chemical bombs entering the Big Apple, officials said.
Enlisting an array of new detection tools, New York's Finest, working with a host of federal and state investigators, have launched a two-pronged assault against terrorists trying to slip bomb-making materials into the city.
On Sunday, about 40 cops using radiation detectors stopped some 50 trucks, trying to determine whether there were traces of radioactive isotopes - the type that would indicate a dirty bomb. They were also looking for other potential explosive ingredients, such as hydrogen peroxide or chlorine, which are favored by al Qaeda.
Inspectors thought they intercepted a radioactive threat a week earlier in lower Manhattan, in the days after the foiled terror plot against Kennedy Airport's aviation fuel system was revealed. But the truck's high reading turned out to be isotopes in the soot of an industrial vacuum.
In addition to these periodic checks, the NYPD's "Operation Rolling Vigilance" has cops at least once a week working with various state and federal investigators at bridges and tunnels, stopping trucks that are licensed to carry hazardous materials.
"We've always been concerned about the potential for trucks and other vehicles to be used to convey explosives or other weapons," said Police Commissioner Ray Kelly. "We also want to screen against the possibility of sensitive cargoes being diverted for use in an attack."
The screeners pay extra attention to dump and cement trucks.
Police officials believe the roving checkpoints and array of inspection technology could thwart potential plots, including ones involving fertilizer-based truck bombs like those used in the attacks on the World Trade Center in 1993 and a federal building in Oklahoma City in 1995.
The NYPD recently put more emphasis on screening shipments of chlorine in response to evidence that it has become a favored ingredient of homemade bombs in Iraq. It can turn into a deadly toxic gas when exposed to air.
The truck inspections are among NYPD security measures - many relying on recent technology - adopted in the wake of 9/11 and various terror scares.
The department has been developing mobile radiation detectors that can be mounted on cars or bicycles.
Officers on the streets and in the subways also have begun wearing pager-like radiation detectors on their belts. About 1,000 of the devices are in use.