I read that scientists are saying halogen light bulbs emit UV radiation which can cause skin cancer. The article also says that a glass or plastic cover over the bulb will eliminate the risk. Are these claims true?"

While it is true that some halogen and fluorescent light bulbs do emit UV radiation, these emissions are low especially when installed in ceiling fittings. UV emissions from all light bulbs and lamps decrease rapidly with distance. 

The Australian Radiation Protection and Nuclear Safety Agency conducted a study into a range of light bulbs and found that although emitting some UVR, none of the halogen lamps tested produced sufficient UV radiation to be hazardous, even at the close distance of 10cm. Furthermore, a glass or plastic cover or shade placed over the bulb can further reduce exposure to UV radiation.