Last year Congress passed a bill aimed at reducing energy consumption. That's a laudable goal. Who doesn't want to save energy?

One of the proposals signed into law, though, goes too far - and, as I recently found out with my kids, can even endanger your health.

Lawmakers mandated the eventual replacement of conventional light bulbs - incandescent, to use the technical term - with compact fluorescent lights, or CFLs. They're supposed to be 4 times more efficient than incandescent bulbs, so it made sense to try them. During a recent weekend, however, the law of unintended consequences hit home in a very personal way.

It was a typical Sunday. The kids were running around. Then, a crash - there went my favorite lamp. Yes, I was upset about the lamp, but as I looked closer, fear gripped my heart. The lamp had one of those new CFL bulbs. They contain mercury.

I immediately shooed my children away. I was too scared to be angry. I then did what anyone with a toxic substance leaking into the floor would do: I cleaned it up.

That was a mistake. You see, if you break one of the new CFL bulbs, it turns out your first course of action should be to open all doors and windows and air out the room. Oh, and everyone should leave for at least 15 minutes. Didn't know that? Funny, neither did I.

You see, the mercury actually changes to vapor at room temperature, and it can be inhaled, as I probably did leaning over the shards of the bulb to clean it up.

My next mistake was to vacuum up the remaining little pieces, since I couldn't seem to corral them with a wet towel. Now I have to throw away my new $400 vacuum. It turns out mercury can get into your vacuum and, once heated in the motor, can infect the air around it.

The one bright spot is that this happened on a hardwood floor. If it had been a carpeted floor, a new study out of Maine actually recommends you cut out the piece of carpeting infected by the mercury to make sure it doesn't get vacuumed up and start swirling around in the air.

Of course, I didn't learn all of this until I spent three hours searching the Internet and talking by phone to the local poison-control office. All I could find on the actual box was that there was indeed mercury in the bulbs and a Web site to check.

So here I sit with the recriminations and the questions. Did my kids get exposed to mercury in the few moments it took to clear the room? And how much was I exposed to while cleaning it up? It was just a light bulb after all, right?

According to the EPA, the amount of mercury in CFLs is less than the tip of a ballpoint pen. This is good - except for the fact that since you can't actually see it, you can't really be sure you cleaned it all up.

Should I pay to have a service come out to monitor whether I cleaned up properly? Should I have my family tested for mercury poisoning? It seems so silly, after all, for just a light bulb. But can you ever be sure enough?

It was my choice to buy the bulb and put it in the lamp. However, under the new law passed last year, incandescent bulbs will begin to be phased out in 2012, and people will no longer have a choice. I wonder how many of them will understand these complex clean-up and disposal procedures to ensure their families' safety?

CFL bulbs may save a lot of energy and help the environment. For some people, they may be the right choice. But we always need to beware the law of unintended consequences. And for now, this mom will be using incandescent bulbs. At least until my lamp breakers are old enough to play responsibly.

Dani Doane is a director of congressional relations at the Heritage Foundation.