There are various indicators that a pressure tank is defective and unfit for use:

• The tank clearly shows traces of damage or alterations.
• Neither a date stamp nor a code indicating that an inspection was performed, or it is past due (inspection period of usually 5 years)
• There is no label with identification and ratings, the name or emblem of the maker, and a statement that it is appropriate for the gas type.
• It does not meet the local requirements for pressure regulators, and the gauges are not labelled to meet the relevant local requirements.
• The tank connection is not perpendicular to the regulator body and is soiled with oils, greases, solvents, or debris.
• The cylinder pressure does not match the pressure rating.
• Damaged and altered pressure release valves

Pick a dependable provider and use pressurised tanks according to all safety regulations to prevent any issues.