According to the U.S. National Library of Medicine, kerosene fumes are not safe to inhale. Negative effects, which vary depending upon how much is inhaled, include difficulty breathing, dizziness, drowsiness, headache and unconsciousness.
When used in portable heaters, kerosene produces several gases. Most dangerous is carbon monoxide, which is poisonous. Nitrogen dioxide is a throat and lung irritant, and sulfur dioxide can cause difficulty breathing. If the fumes from a heater are not removed by a chimney, the gases are released into the room. The gases are especially dangerous to high-risk groups, including people with asthma, seniors and children. Because of the fumes and the potential as a fire hazard, some areas have banned home use of kerosene heaters.