WAS ALL IT TOOK TO CREATE THIS VAPOR CLOUD, MAKING IT DIFFICULT FOR ANYONE NEARBY TO EVEN BREATHE. JUST HOURS AFTER THE GREAT WOLF LODGE OPENED ITS NEWEST HOTEL AND WATER PARK OUTSIDE OF HOUSTON, CALLS STARTED POURING INTO 911. THE GRAND OPENING CELEBRATION QUICKLY TURNING INTO A DANGEROUS HAZMAT SITUATION. THIS AREAL VIDEO CAPTURING FIRST RESPONDERS CONVERGING ON THE SCENE TO HELP. >> SEVERAL ARE HAVING BREATHING DIFFICULTIES AFTER INHALING SOME SORT OF CHEMICAL. >> Reporter: AUTHORITIES SAY A CHEMICAL REACTION HAPPENED IN A POOL HOUSE BEHIND THE LODGE WHEN A THIRD PARTY CONTRACTOR ALLEGEDLY FAILED TO PROPERLY HANDLE TWO CLEANING AGENTS. >> THE CHEMICALS WEREN'T SPILLED, THEY WERE MIXED TOGETHER IN A TANK. >> Reporter: AUTHORITIES SAY THE MIX-UP BECAME APPARENT AFTER ONLY A FEW SECONDS, WHEN A CHEMICAL REACTION OF HYDROFLUORIC ACID AND CHLORINE CREATED A DANGEROUS VAPOR. >> THE CLOUD AFFECTED THE PEOPLE THAT WERE WORKING AROUND THAT AREA. SO WE TRANSPORTED 16 PEOPLE TO THE HOSPITAL. >> Reporter: THAT GROUP INCLUDED PARK EMPLOYEES AND CONSTRUCTION WORKERS, BUT NO GUESTS AT THE HOTEL WERE EXPOSED. AMONG THOSE ON HAND FOR THE GRAND OPENING, SINGER KELLY ROWLAND, FORMER OF DESTINY'S CHILD, WHO WAS THERE WITH HER FAMILY. >> JUST EXCITED TO SEE THEIR SMILING FACES AND HAPPY TO SEE THAT THEY'RE ENJOYING BEING INNOCENT AND YOUNG AND HAPPY AND JOYFUL. >> Reporter: THE CITY OF WEBSTER SAYS NO CHEMICALS WERE DETECTED IN THE WATER PARK OR HOTEL. AND THE GREAT WOLF LODGE LATER SHARED THEY RECEIVED THE ALL-CLEAR TO OPEN THE RESORT AND ALL WATER PARK ATTRACTIONS. NOW, THAT SITUATION WAS QUICKLY CONTAINED. AND WE ARE TOLD IT WILL NOT AFFLICT THE LODGE'S OPERATIONS TODAY. MEANWHILE, AN ENVIRONMENTAL COMPANY IS WORKING WITH THE GREAT WOLF LODGE AND