MDF (medium-density fiberboard) is a type of engineered wood product that is made by binding wood fibers with synthetic resin under high pressure and heat. MDF dust can be dangerous to health when inhaled because it contains a mixture of wood dust, synthetic resin, and other chemicals used during the manufacturing process. Here are some reasons why MDF dust can be harmful:

1. Respiratory problems: MDF dust can cause respiratory problems such as coughing, wheezing, and shortness of breath. Long-term exposure to MDF dust can also cause chronic bronchitis and other lung diseases.

2. Irritation of the eyes, nose, and throat: MDF dust can irritate the eyes, nose, and throat, causing redness, itchiness, and soreness.

3. Skin irritation: MDF dust can cause skin irritation and rashes, particularly in people who have sensitive skin.

4. Carcinogenicity: MDF dust contains formaldehyde, a known human carcinogen. Formaldehyde is used as a binder in MDF and is released into the air as a gas when MDF is cut, sanded, or otherwise worked on.

To minimize the risks associated with MDF dust exposure, it is recommended to wear appropriate personal protective equipment, such as a respirator, goggles, and gloves, when working with MDF. It is also important to work in a well-ventilated area and to avoid generating dust as much as possible by using dust collection systems or wet cutting methods.