Dehumidifiers typically do not contain mercury. Mercury is a hazardous substance that has been phased out of many consumer products due to its toxicity and environmental risks. Dehumidifiers are designed to remove excess moisture from the air and are not known to incorporate mercury as a component.  However, it's essential to check the specific model and manufacturer's information for your dehumidifier to confirm its components and any potentially hazardous materials used in its construction. If you have concerns about mercury or other hazardous materials in your dehumidifier, you can contact the manufacturer or refer to the product's user manual for information on its composition and safety precautions.