They had to drill a hole into the cylinder, evacuate the gas and recontainerize it before the gas could be sampled. Now that the big roundup is over, any future disposal costs for unknown gas cylinders or gas cylinders which have had their valves changed will be charged back to the laboratories which generate them. So please dispose of your cylinders while they still have labels and operable valves. They are used to sediment cells, large particles, and macromolecular precipitates from small volumes. Solutions being centrifuged at high speed may form aerosols due to the high forces involved, especially if proper operating procedures are not followed or if a tube seal fails.
Aerosols are the main cause of micro-centrifuge contamination.
Aerosols can escape from the centrifuge unit and become dispersed in the air. Therefore, if you are using radioactive, toxic, or pathogenic material, be aware of all the characteristics of the material and the hazards associated with it should leakage occur during centrifugation. Designate and label specific micro-centrifuges for radioactive or hazardous material use. Inform your group members. Operate those centrifuges in a fume hood or provide controlled ventilation or isolation for the unit.