There are many positives for CF bulbs (compact fluorescent--the curly ones), though there is one downside: the trace amounts of mercury. Mercury is a toxic element, and is very harmful to the environment. If you have burned-out CF bulbs, you can return them to the place that you purchased them. They will properly dispose of them there. Break a CF bulb? There are some guidelines that you must follow! Read here to see the guidelines that EPA.gov has given.