21.   The gas had come from two canisters thought to have contained pepper gas set off inside a crowded nightclub early Sunday just as the lights were cut.

22.   The Tokyo area was subsequently hit by a series of copy-cat attacks on crowded trains, sometimes involving pepper gas.

23.   They also will carry a potent pepper gas.

24.   Police used pepper gas to quell the uprising at the center, which has been the subject of complaints over conditions and food.