"Samples will be taken according to a very strict protocol and these samples will be analysed," said Darcy Christen, spokesman for the Institute of Radiation Physics, University of Lausanne, Switzerland.
"In order to do these analyses, to check, cross check and double cross check, it will take several months and I don't think we'll have anything tangible available before March or April next year," he told newspersons.
Claiming the need for strict secrecy given "the sanctity of this event", Palestinian officials did not allow the media to watch the investigators go about their work. Incidentally, an autopsy was not carried out when Arafat passed away at a French military hospital in Paris on Nov 11, 2004.
Most Palestinians believe that Israel poisoned their late leader when he was put under house arrest here but Tel Aviv has repeatedly denied any wrongdoing.
Earlier this year, prosecutors in France ordered a murder investigation after al-Jazeera TV highlighted that Swiss scientists at the Institute of Radiation Physics had discovered "significant" traces of a radioactive substance Polonium-210 in Arafat's clothes, headdress and toothbrush.
His widow Suha handed over the personal belongings to the scientists so that they could conduct detailed forensic tests. On Jul 9, Palestinian President Mahmoud Abbas accepted Suha's request for an exhumation.
Investigators taking part in the process today will go back to their respective countries and examine the samples closely for traces of Polonium-210 or other lethal substances.
It is noteworthy that Polonium-210 caused the unnatural death of ex-KGB officer Alexander Litvinenko. The Russian spy who had defected to the West died at a London hospital in Nov 2006.