Investigators are forced to leave unstable air terminal

The renewed sound of cracking concrete forced rescue workers and investigators yesterday to evacuate what remains of the departure lounge which collapsed at Charles de Gaulle airport north of Paris.

The renewed sound of cracking concrete forced rescue workers and investigators yesterday to evacuate what remains of the departure lounge which collapsed at Charles de Gaulle airport north of Paris.

The fresh signs of instability may force the airport authority to demolish the whole of the, tubular building, opened less than a year ago as part of a €750m (£500m) showpiece terminal for France's premier airport.

The death toll from Sunday's collapse was reduced to four yesterday. Sniffer dogs located what appeared to be two corpses under the rubble but rescuers made the gruesome discovery that it was one person who had been cut in two.

Two of the dead were Chinese passengers, changing planes at Paris on their way from Shanghai to New York. The others have not yet been named.

Two separate investigations into the collapse of a 20m-long section of the departure lounge - one a criminal inquiry into possible manslaughter and one an administrative inquiry - got under way yesterday.

The architect of the 700m-long, gently curving building, regarded as a showcase of French engineering style and skill is Paul Andreu. One of France's leading architects, he said he was "distraught" about the collapse.

He flew back to Paris from China, where he was supervising the building of a new state theatre in Beijing. "I can't explain what happened. I just don't understand it," M. Andreu said.

Although the design of terminal 2E was "adventurous", he said, there was nothing revolutionary in the building methods used. Airport and French government officials suggested that a fault in construction, rather than design, was likely to have caused the accident. The plan for the departure lounge, projecting into the airport and known as La Jétee (the jetty), had been checked and cross-checked by computer, they said.

The president of Aeroports de Paris (ADP), Pierre Graff, said he would have no hesitation in ordering the whole concrete, steel and glass departure lounge to be demolished if necessary.

"If all the (concrete) rings that make up this terminal are beyond repair, we'll tear it all down, of course," M. Graff said. "We will take no risks when it comes to safety." The prospect of such a demolition - involving about one third of the entire terminal - seemed to draw closer yesterday afternoon when rescue workers reported new sounds of cracking in the remaining sections of the roof of the departure lounge. All rescue workers and investigators were ordered out of the building.

The vaulted roof collapsed just before 7am on Sunday, showering concrete, steel girders and glass into a passenger lounge. The walls of the building collapsed in turn, crushing a walkway and several vehicles.

The accident is not just a blow to France's engineering pride. It threatens the entire strategy of Aeroports de Paris and Air France to develop Charles de Gaulle Airport as the premier European hub between transcontinental and European flights. Terminal 2E had been designed to accommodate the new super jumbo jets now under construction by Airbus.

With Terminal 2F next door, and two further satellites yet to be built, it was intended as the centrepiece of an almost entirely new airport at the eastern end of the site. It was conceived as a perfect, passenger interchange point - exclusively reserved for Air France, its new acquisition KLM and its partners in the "Skyteam alliance", including Delta and Aeroflot.

Experts suggested it might be two to three years before the collapsed part of the terminal could be replaced.