As if anyone needs to be told, tear gas is not fun.

I found this out the hard way, when a smoking canister landed near my feet outside a gated entrance to the interior of Quebec City, where 34 world leaders were busy hammering out a free trade agreement at the Summit of the Americas last weekend.

It was obvious things could get ugly. Many of the protesters already had their faces covered before the first rock or bottle flew. They were clearly preparing for a face-off with the hundreds of police clad in riot gear.

But anticipating trouble is one thing. Being in the middle of battle for 2 1/2 days is something else.

Our satellite truck and camera position were about 50 yards outside the 10-foot chain-link fence that formed a security perimeter. We were in the middle of a crowd ranging in size from hundreds to thousands through the weekend, and tensions rarely eased.

Both sides in this classic showdown appeared tireless — young, defiant rebels on our side of the fence, tough-looking, heavily armored and helmeted police on the other. The most violent demonstrators were armed with rocks, bottles, sticks, golf balls, marbles, hockey pucks, paint balls, and attitude; the cops with water cannons, bean bag guns, rubber bullets, and tear gas launchers.

The protestors moved closer and closer to the fence, their decibel levels rising and numbers increasing. When rocks and bottles started flying, the cops fired back, spraying water and shooting tear gas cans in an ongoing attempt to disperse the crowd.

Most of the cans flew relatively short distances before being picked up by athletic-looking guys in heavy-duty work gloves and heaved back over the fence at police. The police never threw them back again. They just fired more fresh ones instead.

Some of the cans traveled much farther, making a toss back out of the question.

Some of the tear gas didn't come in cans at all, but in spinning balls that spit smoke in several directions. These were much harder to pick up, and many times the gas was so thick that demonstrators couldn't even find the device.

In any case, the cans worked, albeit temporarily. People ran for cover, some tripping and falling, many coughing and wiping their eyes and gasping.

I found out the hard way that even with a gas mask on, it's not a good idea to breathe in the middle of a fresh cloud of tear gas. Some of it invariably gets inside the mask. Then it starts to hurt. Bad. Your eyes water, your face itches and your nose opens up. Rubbing your eyes and skin only makes it worse. The burning lasts for a few minutes ... but the sting in the air lingers for much longer. Hours after the last can exploded, gusts of wind carried the symptoms back to us.

Over and over, we watched people collapse onto the curb, overcome by the fumes. They bent over with their hands on their knees, coughing and spitting, before stumbling away from the constant aerial assault.

There were also a lot of protestors soaked by water cannons with spray ranging from a soft plume to a hard jolt that actually knocked down a woman wearing carnival stilts and a Statue of Liberty costume.

A number of times, we in the media had our own confrontations with protestors. We, or the companies we worked for, were guilty partners in the evils of globalization and our lenses distorted the truth, they said. The satellite truck was attacked, sprayed with graffiti (one message: the word "LIES" under "Global", the Canadian television network which owned the truck).

At one point, photographer Scott Wilder and I were shooting pictures of a guy pulling bricks out of the sidewalk to use as ammo. He ran up to the camera with his hand out to block the lens. Twice, protestors picked up tear gas cans and threw them at our satellite truck instead of back over the fence at police.

And working in a gas mask isn't easy. First of all, it's uncomfortable. The straps are pulled tight in several directions across the head to prevent fumes from seeping in. It's hot inside, and while lifting the bottom of the mask helps, it also allows a bit of the gas in as well. One anchor told me I reminded her of a character from a Star Wars film.

It was well worth the abuse, though. Our sound man, John Kisala, and producer, Carlos Van Meek, didn't have masks for part of the day (we were sharing them with the Canadian crew). They ran for cover every time another cloud rolled in, coughing and tearing up. I kept my mask on.

The percentage of protestors resorting to violence appeared to be relatively small, perhaps 10 percent of the total, but their actions created a huge distraction, making it difficult to hear whether there were any reasonable or intelligent voices in the crowd.

Perhaps the next group of demonstrators will figure that out. But I'm bringing my gas mask, just in case.

To comment on this article, write rick.leventhal@foxnews.com.