Coal-fired stoves can cause fires, and improper ventilation can cause carbon monoxide poisoning. Carbon monoxide is odorless, but detectors can warn homeowners before a dangerous amount of carbon monoxide builds.
When coal burns, it creates a number of potentially dangerous chemicals, requiring the use of a chimney. If the chimney is obstructed, smoke and chemicals can quickly fill a room. In addition to carbon monoxide, some types of coal can also produce sulfur dioxide. Some of the chemicals generated from burning coal are corrosive, so chimney inspections are important to prevent collapses.
Coal fires must be tended regularly, and small mistakes can cause burning embers to enter a room. Opening the door to the unit too quickly can cause a flash of fire as oxygen reaches the coal, so care must be taken when maintaining the unit. Appropriate tools for tending the fire can help prevent burns.
One of the biggest dangers of coal is the ash it generates when burned. The light weight of ash allows it to spread through a room, potentially aggravating respiratory problems. Ash is also hot when it is first removed from the stove, so it's important to place it in a container designed to handle hot items.