(AP) - A Sept. 13, 2001, file photo of James Symington and...

(BioArts) - The logo of BioArts. A dog that sniffed out survivors from under the rubble of New York's World Trade Center after the 2001 terror strikes is to be cloned, the California-based firm conducting the procedure said.(BioArts)

(Reuters) - The World Trade Center site in New York, June 25, 2008. (Mike Segar/Reuters)

(Reuters) - The World Trade Center site in New York, June 25, 2008. (Mike Segar/Reuters)

(AFP/Getty Images/File) - Construction continues at the World Trade Center site in New York City. Construction of skyscrapers and an underground transport hub to replace the World Trade Center towers destroyed in the September 11 terror attacks will be delayed for years and cost far more than planned, New York officials said Monday.(AFP/Getty Images/File/Stephen Chernin)

(AFP/File) - Construction workers and heavy machinery operate at the building site at "Ground Zero" of the World Trade Center development, in New York, 2007. Construction of skyscrapers and an underground transport hub to replace the World Trade Center destroyed in the September 11 terror attack will be delayed for years and cost...

(AP) - This file picture provided by Silverstein Properties, Inc. in Sept 2006 shows an artist's rendering of three proposed designs for...

(AP) - In this file photo of Friday, June 20, 2008, construction cranes work above the Freedom Tower foundations at the World Trade Center site in New York. The World Trade Center's owner on Monday, June 30, 2008, proposed scrapping...

(Reuters) - Construction Work continues at the Western section of the World Trade Center site in New York, June 25, 2008. (Mike Segar/Reuters)

(Reuters) - One World Trade Center, the Freedom Tower, in an undated illustration. (File/Reuters)

(AP) - In this March 27, 2007 file photo, the dismantling of the former Deutsche Bank building, center, continues at the World Trade Center site, foreground, in New York. It will cost another $37.5 million to deconstruct a contaminated skyscraper at New York's ground zero, it was announced Friday, June 27, 2008. (AP Photo/Mark Lennihan, file)

(Reuters) - A worker stands amid remains of the former World Trade Center towers and complex at the World Trade Center site in New York, June 25, 2008. Workers are currently drilling, blasting and excavating down to solid bedrock in this section before pouring the footings for future World Trade...

(Reuters) - Scott Thompson, a Construction Project Executive with Silverstein Properties, the main developer at the World Trade Center site, points to work continuing at the site in New York, June 25, 2008. Workers are currently drilling, blasting and excavating down...

(Reuters) - A view of a portion of the destroyed remains of the former World Trade Center complex at the World Trade Center site in New York, June 25, 2008. Workers are currently drilling, blasting and excavating down to solid bedrock in this section...

(Reuters) - Construction continues beneath giant banners depicting the future towers at the World Trade Center site in New York, June 25, 2008. Workers are currently drilling, blasting and excavating down to solid bedrock in the Eastern section of the site before pouring the footings for future World Trade Center towers...

(Reuters) - Construction continues beneath giant banners depicting the future towers at the World Trade Center site in New York, June 25, 2008. Workers are currently drilling, blasting and excavating down to solid bedrock in the Eastern section of the site before pouring the footings for...

(Reuters) - Heavy machinery breaks rock for removal at the World Trade Center site in New York, June 25, 2008. Workers are currently drilling, blasting and excavating down to solid bedrock in this section before pouring the footings for future World Trade Center towers Two, Three and Four. Picture taken June 25, 2008. ...

(Reuters) - A worker walks at the base of the former World Trade Center site in New York, June 25, 2008. Workers are currently drilling, blasting and excavating down to solid bedrock in this section before pouring the footings for future World Trade Center towers Two, Three and Four. REUTERS/Mike Segar (UNITED...

(Reuters) - A view of a portion of the destroyed remains of the former World Trade Center complex with construction workers (front) as seen from the base of a portion of the World...