Although hydrogen-oxygen balloon explosions are popular demonstrations, the acoustic impulse created poses a hearing damage risk if the peak level exceeds 140 dB at the listener's ear. The results of acoustical measurements of hydrogen-oxygen balloons of varying volume and oxygen content are described. It is shown that hydrogen balloons may be used without auditory risk to typically situated participants. It is further shown that even small (approximately 0.1 mol total) hydrogen-oxygen balloons cannot be exploded without precaution, that is, ensuring that participants have hearing protection or are located sufficiently far away. In all cases, it is recommended that the presenter wear hearing protection. (Contains 6 figures and 1 table.)