My own personal experience with tear gas and pepper spray is quite limited. A couple of brief encounters with pepper spray from a distance; I've been a little too close for comfort to an Israeli 'sound grenade'; I've been in the cloud of grey smoke that Israeli tanks secrete all over the place when they want to conceal themselves somewhat; but the main experience was at the anti-FTAA protests in Quebec City in 2001, when police apparently used thousands of canisters of tear gas. The strangest moment was the morning of the second day, after we'd thought we were used to the gas of the previous day. They somehow changed the concoction, so we who went out bravely into the clouds found ourselves choking and puking anew, faced with the new brew.
What Israel is doing in the West Bank now, as Jason Brooks presents in Counterpunch, seems a lot worse. In his words: "Israel's repeated use of highly toxic unknown chemicals against Palestinian civilians is now an open secret. We can expect these attacks to continue until a concerted effort is made to determine the facts and hold Israel accountable. So far, the international human rights community has steadfastly ignored the mounting evidence."