Let There Be Light (Maybe)

Both Kiwiblog and Jafapete blog about the latest news about compact fluorescent lights (CFLs) – that they are potential fire hazards. I recall that Ian Wishart had a long article on this in the last Investigate magazine, which, I thought, was a curious mixture of scare-mongering and useful fact. The overly scary bit was mostly about mercury (the metal, not the planet) but there was a section on fire hazard potential that made a lot of sense.

Of course, virtually any electrical appliance could be considered a fire hazard, including incandescent bulbs. CFLs, however, contain quite complex circuitry inside the stem (also known as the ballast). As CFLs fall in price, the components in the electronic ballast become cheaper and less durable. This is not a huge problem if the bulb is inserted in upward or sideways pointing sockets, but it can cause early failure, burn-out and, possibly, fire in a downward socket. This is because the heat of the CFL makes the components hot. This is made much worse by recessed sockets.

The simplest solution to this would be to leave incandescents in your downward sockets. If incandescent bulbs are banned, your options are tungsten lights or high-quality CFLs with heat cut-out switches built in to the ballast. Neither of these will be cheap.

So fire is probably not going to be a common problem. How about mercury poisoning?

A cold CFL has most of its mercury in amalgam form. This amalgam vapourises very fast, so even breaking a cold CFL can put mercury into the atmosphere. However, even if all the mercury in a CFL became vapour, it would only barely reach the recommended limit for chronic exposure (300ng/CuM) in a small, ventilated room. This is cause to be cautious, but not cause to panic.

The real problem with CFLs is with disposal, either of a broken bulb or a whole, dead one. There needs to be disposal instructions on the packet of every bulb sold and there needs to be some sort of special place to deposit the dead and broken bulbs. Just ploughing them into the city dump is unacceptable.

If you break a bulb you need to ventilate the room to the outside for at least an hour; then, wearing gloves, you need to sweep the bulb into a sealable container and dispose of the gloves and dustpan and brush. How many people are going to do this? Mercury is a cumulative poison – it is made worse by repeated and prolonged exposure so we need to be certain that we have a proper disposal plan in place before we use the things.

I am not in favour of banning incandescent bulbs simply to achieve some small gain in energy savings. It is an unwonted intrusion into ordinary household affairs for no appreciable benefit and at some additional risk. It is a doubly stupid idea if we don’t even have proper disposal facilities in place before we start.

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