(The following article by William Neuman was posted on the New York Times website on October 3.)
NEW YORK — When security officials first installed a system of sensors at Grand Central Terminal to sniff the air for signs of a poison gas or chemical attack, they had to learn to tell the difference between a janitor and a terrorist.
Technicians found that a person walking by with a mop and bucket full of floor cleaner could trigger the chemical sensors.
Now, two years after the system was rushed into place in time for the Republican National Convention in the summer of 2004, officials at the Metropolitan Transportation Authority are satisfied that they can use the equipment to distinguish between a real threat and Mr. Clean. They have decided to spend $3.9 million to further upgrade the network of sensors at Grand Central Terminal and install a similar system in Pennsylvania Station.
A spokesman for Amtrak said it also had plans to place monitors in the portion of Penn Station it controls, and to put chemical-detection systems in place in three other stations, in Philadelphia, Washington and Chicago.
The system, known as Protect (the acronym stands for Program for Response Options and Technology Enhancements for Chemical/Biological Terrorism), includes sensors, also called sniffers, that continually suck in air and analyze it for chemical toxins and gases, said Jamie Edgar, a vice president of Smiths Detection-LiveWave, the company that manufactures and installs the equipment.
The sensors, housed in nondescript metal boxes around Grand Central Terminal, are combined with concealed video cameras that let technicians or law enforcement personnel observe the area around the monitors for signs of an attack — or for that telltale bucket and mop. Data is analyzed with software that can predict the direction of a chemical plume, to aid officials in coordinating an evacuation.
The system was developed by Argonne National Laboratory after the sarin gas attack in the Tokyo subway in 1995. It was first tested in the subway system in Washington in December 2001, and by 2003 it had been installed in several stations there. In the summer of 2004 it was installed by the Department of Homeland Security in Grand Central Terminal and in a transit facility in Boston, where the Democratic National Convention was held.
At Grand Central, the system is one of several safeguards, including radiation monitors and sensors that detect biological or germ warfare agents.
The biological detectors are checked manually once a day. The chemical sensors, however, are computerized and constantly feed data into a monitoring system that can alert the terminal’s security staff when a problem occurs.
Anthony J. Policastro, deputy director of the Infrastructure Assurance Center at Argonne National Laboratory, said that the system at Grand Central Terminal was initially meant to be temporary and that it was not until after the Republican convention that Homeland Security officials decided to leave it in place.
That required a good deal of additional work, including improving wired and wireless connections and adapting the system to the terminal’s unique conditions, he said.
Technicians discovered that Grand Central was both a dirtier and, in its way, a cleaner place than the Washington subway. People who worked on the system said that brake dust from trains fouled filters, which had to be changed more frequently. Fumes from diesel engines caused other problems.
And then there were those janitors. The technicians encountered an array of cleaning products in the terminal, and adjustments were needed in the sensors and software.
“It’s a more difficult environment in that terminal, in terms of dust, dirt and chemicals,” Dr. Policastro said.
Lewis D. Schiliro, who was hired last January as director of Inter-Agency Preparedness for the Metropolitan Transportation Authority, said there were other problems to overcome.
Technicians had to make the detection system’s software work with computer programs that the authority already had in place for emergency management.
And the authority had to develop a plan with its own police force, the city police, the Fire Department and the city health department on how to coordinate their response in the event the sensors actually detected an attack.
“It’s not that you have a magic wand and can wave it and make all these things happen,” Mr. Schiliro said.
He said that in April or May his staff concluded it was satisfied with the Protect system and that he decided then to expand it to Penn Station.
The procurement process took four or five months. The contract did not have to be offered for public bid, since Smiths Detection-LiveWave is the only company that offers the system, but further approvals were required within the authority, Mr. Schiliro said, and it took time to negotiate the deal with the company.
Last week, the authority’s board agreed to spend $611,000 to upgrade the system at Grand Central and $1.6 million to install the new system at Penn Station. A three-year maintenance contract covering both facilities, with an option for two additional years, will cost an extra $1.7 million.
Mr. Schiliro said that it would take time to manufacture and install the sensors and that he expected the new system to be fully in place in the areas of Penn Station controlled by the authority in six to eight months. (Biological monitors and radiation detectors are already installed there.)
Amtrak said that in addition to installing the sensors in Penn Station, it would do so in Union Station in Chicago, 30th Street Station in Philadelphia and Union Station in Washington. The installation at the four sites will take place over the next two years at a cost of $5.5 million, said an Amtrak spokeswoman, Karina Romero.
Mr. Schiliro said the Metropolitan Transportation Authority might eventually decide to place chemical detectors in other heavily used stations, such as Jamaica, in Queens, Atlantic Avenue, in Brooklyn, and the 125th Street station that serves the Lexington Avenue subway line and Metro-North in Harlem. But the authority has not put in orders for the equipment, and Mr. Schiliro said there was no timetable for when it might do so.