Over the past year, I have seen compact fluorescent light bulbs catch on fire three times during inspections in other people’s homes, and once in my own home.

On the first occasion, during a home inspection here in Tracy, the buyer and the buyer’s agent and I were walking through the house discussing my findings when we smelled smoke. We walked into the front room, and the bulb inside of a ceiling fan was on fire. The agent promptly called the Tracy Fire Department, and they were there in a matter of minutes.

Fortunately, because the lamp was metal, the fire went out on its own fairly quickly; however, the firefighters scanned it with their infrared camera and found that the bulb was still extremely hot at its base.

While the firefighters were checking out the lamp, I was discussing the issue with the fire captain. I had just received a product warning notice on CFL bulbs in the past week, saying that some makes of CFL bulbs should not be installed in light fixtures where the top of the bulb is pointing down or in any other direction other than upright. In the case of this ceiling fan, the bulbs were installed pointing down at an angle from the fixture.

It seems that installing them in this manner causes the ballast at the base of the bulbs to heat up significantly hotter than if they are installed upright. Bulbs have been reported to catch fire at the base and release mercury vapor as they burn.

This may not be the case with all CFL bulbs. Still, certain manufacturers recommend on the packaging that the bulbs be installed only in an upright position, not laterally or upside down.

On two other occasions, I have witnessed compact fluorescent bulbs catch on fire at the base during home inspections. One was upside down in a ceiling light fixture, and one was installed laterally in a wall fixture in a garage. The one in the garage caused the paper on the sheetrock next to the fixture to catch fire momentarily.

The bulb that caught fire at my own home was installed laterally in a garage-door opener. The light bulb first started flickering, and then it began to smoke and started burning at the base.

Fortunately, no serious fires resulted, but in each case, the power was turned off immediately when the problem was identified. Had this occurred unwitnessed, the outcome might have been dramatically different.

My suggestion to home owners who buy compact fluorescent bulbs is to first read the packaging to determine if there are any warnings, such as installing them only in an upright position. I also recommend from personal experience that you avoid installing CFL bulbs upside down (as in ceiling lamps or ceiling fans), regardless of instructions on the packaging, to avoid the possibility of the bulbs becoming overheated and catching fire — and releasing mercury vapor into your home — just to be safe.

• Larry Hite, owner of Tracy Home Inspections and Dirty Jobs Crime Scene Cleaners, is a certified mold, chimney and fireplace inspector. He can be reached at larryhite@sbcglobal.net.