Asthma attack in a spa pool: what could be the cause?

CASE SCENARIO

June, a 65-year-old woman, was in good general health. She had been taking an ACE inhibitor for the past 10 years for hypertension, which had been well controlled. She had experienced only occasional episodes of postinfectious asthma that had quickly responded to her inhaler. Three days prior to her presentation, June had completed her regular swim in the pool in her apartment complex and then, as usual, had hopped into the warm spa pool. However, almost as soon as she turned on the bubbles in the spa, she started to feel her chest tightening up, started to wheeze and cough uncontrollably and she became dyspnoeic. She managed to get out of the spa and return to her apartment where she used her inhaler almost continually for the next hour until her symptoms settled somewhat. When the incident was investigated later that day, it was found that there had been a malfunction of the chlorine probe and the warm spa water had contained a high concentration of chlorine.

Has June experienced an acute episode of asthma or could there have been a direct toxic effect of chlorine on her airways?