Abstract: A unit in the form of a bubble pack for creating an anaerobic gaseous atmosphere in an upright container and for indicating the presence of the anaerobic atmosphere in the container. One bubble of the pack houses acid-containing ampoules while another bubble houses a tablet which generates hydrogen and carbon dioxide when activated by squeezing the first bubble to crush the ampoules and release the acid. Gas flows from the second bubble, through the first bubble and then into the container and enters still another bubble which houses an ampoule containing a redox color indicating liquid. When the latter ampoule is crushed, the liquid moistens an absorbent pad which changes colors as the atmosphere of the container changes from aerobic to anaerobic. The pack also carries catalyst pellets to promote a reaction between the generated hydrogen and the oxygen in the container.