It's estimated that the World Trade Center's Twin Towers were constructed of enough concrete to build a sidewalk from New York to Washington, D.C. Their collapse pulverized all of that concrete into dust and tiny pieces, most no bigger than a quarter, that covered the 16-acre site along with steel beams, the contents of offices from some 500 companies, airplane parts, and rescue equipment, as well as remains from 3,835 victims of the Sept. 11 terrorist attacks.

Working in that difficult environment, teams from the Fire Department of New York and other search personnel have had the monumental task of recovering and cataloging thousands of pieces of evidence so investigators could map where items are recovered and piece together what happened. That's critical because the area is not only a crash site but also a crime scene. At first, searchers in the recovery effort cataloged evidence manually--tagging each piece as it was recovered, then writing a description of each article and its approximate position in the mounds of rubble that the recovery teams called "the pile." Personnel later entered the information written on pieces of paper into a database they're creating to track the positions where recovered items are found.

That manual process proved to be too time-consuming and error-prone, so the Fire Department looked for ways to automate the job. It found a solution using rugged handheld computers from Symbol Technologies Inc. and location-based applications developed by Links Point Inc. specifically for the recovery effort. Symbol and Links Point had met with city and federal officials to discuss ways to automate the cataloging of evidence, and developed their evidence-recovery application within two days of receiving approval from the City of New York.

Searchers use handhelds and location-based apps to catalog evidence

One person from each of the eight recovery units working at the site at any given time now carries a Symbol PPT handheld device equipped with a bar-code reader attachment and a global positioning system receiver. When searchers recover a significant piece of evidence, they put a bar-coded tag on the item, scan the tag into the Symbol handheld to create an electronic record, and choose from a scroll-down list of article descriptions on the handheld's screen. As each item is tagged and described, the exact location of the item is recorded from the GPS attachment, along with the exact date and time.

At the end of a shift, searchers place the handhelds in a cradle to download data on the day's finds to a central database; the city's emergency mapping agency uses the data to produce maps of where articles were found. The categories of items and locations where they're recovered help the city reconstruct where firefighting equipment was when the buildings collapsed, along with the locations of firefighters, police officers, and civilians killed at the site.

The types of apparatus cataloged include battalion and division cars, fire engines, and ladder engines; and a variety of firefighting equipment. Such information can help the Fire Department analyze its response times in the hopes of improving its response to future emergencies.