DC9 IS EVACED WHEN A PAX RELEASES PEPPER SPRAY EITHER INTENTIONALLY OR UNINTENTIONALLY.

Narrative

AT APPROX 500 FT AGL ON A VISUAL APCH THE FLT ATTENDANTS RANG US REPEATEDLY FROM THE CABIN. I BRIEFLY CONSIDERED WHETHER WE SHOULD GAR; BUT DECIDED TO LAND AND THEN TALK TO THEM. THE FO CONTINUED TO MONITOR MY APCH AND LNDG WHILE THE FLT ATTENDANTS RANG US WITH INCREASING URGENCY. DURING THE LNDG ROLLOUT; THE FLT ATTENDANTS BEGAN TO BANG ON THE COCKPIT DOOR. THE FO THEN PICKED UP THE HANDSET. HE TOLD ME THAT THEY WERE 'CHOKING' DUE TO SOME KIND OF 'GAS' IN THE CABIN. HE THEN DECLARED AN EMER WITH TWR AND TOLD THEM TO EXPECT AN EVAC. I QUICKLY STOPPED THE PLANE ON A HIGHSPD TXWY; SET THE BRAKE; TURNED OFF BOTH AIR CONDITIONING PACKS; AND WITH THE FO'S HELP; CONFIGURED THE PLANE FOR EVAC. I THEN HAD THE FO OPEN THE COCKPIT DOOR. AT THAT POINT I COULD SENSE NO 'GAS.' I HAD THE FLT ATTENDANTS OPEN THE FORWARD GALLEY SVC DOOR AND THE MAIN CABIN DOOR. THE FLT ATTENDANTS SAID THE GAS WAS DISSIPATING IN THE CABIN. BECAUSE OF THIS; I HAD THE PAX EVAC DOWN THE FORWARD STAIRS RATHER THAN RISK INJURY ON THE SLIDES. THIS WAS DONE IN AN ORDERLY MANNER. AFTERWARDS; THE PLANE WAS INSPECTED BY A POLICEMAN AND FIRE FIGHTERS. THEY CONCLUDED THAT SOMEONE HAD RELEASED PEPPER SPRAY INTO THE CABIN. (COMPANY MECHS FOUND NOTHING WRONG WITH THE PLANE.) UNFORTUNATELY NEITHER THE CULPRIT OR THE PEPPER SPRAY DEVICE WAS DISCOVERED. LATER I LEARNED THAT CARRYING PEPPER SPRAY IS QUITE PREVALENT. ALSO; THERE HAVE BEEN OTHER INSTANCES OF ACCIDENTAL OR INTENTIONAL RELEASE IN PUBLIC PLACES (INCLUDING ON ANOTHER ACFT). THESE DEVICES ARE QUITE SMALL AND MUST BE DIFFICULT FOR SECURITY TO SCREEN. WE WERE QUITE FORTUNATE THAT ONLY 2 PAX HAD TO BE TREATED FOR EYE AND THROAT IRRITATION. (I HATE TO THINK WHAT WOULD HAVE HAPPENED HAD WE GONE AROUND!) I AM CONCERNED THAT THIS WILL HAPPEN AGAIN WITH MORE SERIOUS CONSEQUENCES.