Senior defense officials told the Israeli newspaper Haaretz that chemicals, including sulfur, are aboard some of the ships of the flotilla seeking to leave Greece later this week in an attempt break the naval blockade of Gaza.
"The picture emerging here is that some of the flotilla participants clearly intend a violent clash," an Israel military source said.
"This is a chemical weapon, and if poured on a soldier, it can paralyze him," a military source said. "If the sulfur is then lit on fire, the soldier will light up like a torch."
Ynetnews.com reported increasing calls by the IDF (Israel Defense Force) to boycott boats trying to break the Gaza blockade in order to deter vessels from joining in future flotillas.
Senior IDF officers said simply sending the ship, the Mavi Marmara, back to Turkey after last year's flotilla incident didn't do enough to deter future organizers from attempting an attack on Israel's legal blockade in Gaza.
Ten ships from the United States, Canada, Italy, Spain, Ireland, Sweden, Greece and Norway will carry an anticipated 292 passengers and 36 journalists -- far fewer than originally expected, and the final number may be even smaller, Ynetnews.com reported.
Ynet said some of the ships will be declared unfit to sail, and the Greek government may withhold departure authorization.
"The situation isn't good, it is true that we will sail with fewer passengers than the previous flotilla but … we must remember that the Turks aren't participating so Israel won't be able to claim that this is an Islamist flotilla, so there are benefits," said Dror Feiler, a flotilla organizer and a former Israeli.