Thousands of Israelis are lining up for gas masks or ordering them by phone, spurred on by fears that any Western military response to last week's alleged chemical weapons attack in Syria could ensnare their own country in war.
Western powers are considering military action to punish the Syrian government for the alleged attack that killed hundreds near Damascus last week.
With speculation mounting that NATO powers might fire cruise missiles into Syria, many in Israel worry that President Bashar al-Assad, embroiled in a 2-1/2 year uprising against his rule, could strike out at the Jewish state in retaliation.
Israeli media reports of Syrian officials threatening retaliation against Israel for any Western strike have only served to heighten the anxiety.
"We live in a crazy region. All it takes is for one crazy person to push a button and you never know, everything can go up in flames," said Victor Bracha, 72, one of those queuing for protective gear at a makeshift distribution center in a shopping mall in Jerusalem.
Maya Avishai, spokeswoman for the Israeli Postal Service, which oversees the distribution of gas masks on behalf of the military's homefront command, said four times as many people as usual had phoned in orders in the past two days.
"Twice as many as usual are showing up at public centers to pick them up. The pressure has been great," Avishai said. There was also talk of expanding the number of centers handing out gas masks to meet demand, she added.
Could violence spread?
Israel has eschewed any involvement in the internal conflicts gripping its Arab neighbors in the past two years, and some Israelis doubt Assad would turn his guns on Israel.
"It is not in his interest, it could bring about his demise more quickly," Israeli Strategic Affairs Minister Yuval Steinitz said on Sunday.
"It would be insane for somebody to try and provoke Israel," he added in remarks to foreign correspondents in Jerusalem on Monday.
Shlomi Goldstein, 32, another shopper at the mall in Jerusalem, said he had no plans to join those queuing for masks, confident that Israel could deter any attack.
"I think Assad wouldn't dare to attack us, he knows that if he did it could be the last thing he ever does," he said.
Israel has provided its citizens with gear to cope with possible chemical or biological attacks since the 1991 Gulf War, when U.S.-led troops drove Iraq out of Kuwait.
During that conflict, Iraq fired Scud missiles into Israel and its leader, Saddam Hussein, threatened a chemical attack on Israel, though he never acted on this.
Three years ago Israel launched a campaign to renew the protection kits. But until last week's attack in Syria, only around 5 million of Israel's 8-million strong population had updated theirs, officials said.
Israel remains technically at war with Syria, which has long demanded an Israeli withdrawal from the strategic Golan Heights, land that Israel captured in a 1967 war.