Ely Karmon, a specialist in biological, chemical and nuclear terrorism at the Interdisciplinary Center Herzliya's Institute for Counterterrorism, told the Jerusalem Post that polonium decays quickly. He said it has a half life of 138 days, meaning that "half of the substance decays every four-and-one-half months."
The high levels of polonium reportedly found by Swiss scientists on Arafat's clothing suggest it was planted recently, Karmon said.
Karmon said Suha Arafat, Arafat's widow, would have been poisoned as well if the clothing was in her custody for eight years. He also cited French medical records that show Arafat's symptoms were not those of polonium poisoning.
The most notorious case of polonium poisoning was Alexander Litvinenko, a former Russian agent who had taken refuge in London. He died there in 2006.
Arafat, the longtime head of the Palestine Liberation Organization, was head of the Palestinian National Authority at the time of his death.