NEW YORK, NY March 10, 2005 —Scientists say a test that begins today will help determine how a toxic gas cloud might disperse in Manhattan. WNYC's Fred Mogul has more.

Samples of odorless, colorless and non-toxic gas will be released in midtown today and will be measured by equipment on Madison Square Garden and various rooftops.

Scientists hope the $10 million Urban Dispersion Program will improve emergency preparedness by determining how a lethal gas could flow in and around the city's air currents.

This is a preliminary trial, with subsequent tests in August and next Spring. It is being run by various federal agencies, including the Energy Department, the Department of Homeland Security and the EPA. For WNYC, I'm Fred Mogul.