The gas commonly used in balloons is helium. Helium is a non-toxic, lighter-than-air gas that provides lift, making it ideal for filling balloons used in celebrations, events, and for decorative purposes. Unlike hydrogen, which is highly flammable and poses significant safety risks, helium is safe and inert, allowing it to be used freely in various applications, including scientific and medical fields. Because of its properties, helium balloons can float for an extended period until the helium gradually escapes through the balloon material. This characteristic makes helium a popular choice for both commercial and personal use in balloon arrangements.