Final answer:
The correct way to dispose of a disposable refrigerant cylinder is by recycling it at a certified facility to prevent environmental pollution.
Step-by-step explanation:
The proper method of discarding a disposable refrigerant cylinder is to recycle it at a certified facility. Throwing it in the regular trash, burying it in the ground, or burning it in an incinerator are not environmentally sound disposal methods. Recycling at certified facilities ensures that harmful materials are processed correctly and do not contribute to air pollution, groundwater contamination, or exacerbation of smog. Landfill and incineration are the two primary methods of waste disposal in the United States; however, neither is a good option for dangerous toxins such as those found in refrigerant cylinders. Companies are responsible for following government safety guidelines for the proper disposal of such materials.