Summer of the exploding laptop!

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To hear some talk about it, you'd think laptops around the world were exploding left and right.

In April, an 11-year-old's unattended Apple iBook in Solon, Iowa, melted the carpet it was sitting on and subsequently caught fire.

Then in June, a Dell laptop exploded into flames at a conference in Japan.

And Wednesday there was a front-page article in the Globe and Mail about the perils of exploding laptops, featuring these two incidents.

But, as mentioned in the Globe article, the U.S. Consumer Product Safety Commission has reported only 43 laptop fires in the United States since 2001, or about 10 every year.

That's the same number of fires caused every year by nightlights.

(Which reminds me of that classic "Summer of the Shark" bit Stephen Colbert did on the Daily Show.)

And given that there are an estimated 60 million laptops in the U.S., that's a pretty good ratio of non-exploding units to exploding units.

Still, to err on the side of caution, Dell has now decided to recall 4.1 million laptops and replace their Sony-made lithium batteries.

This was the third recall of Dell batteries in the past five years and the computer maker launched a Web site, http://www.dellbatteryprogram.com, which described the affected models and how to get an exchange.

In announcing the recall, Dell reported six incidents of battery overheating in its recent line of notebooks, resulting in property damage but no injuries.

Linda Nazar, the University of Waterloo chemistry professor interviewed for the article, later posted a comment on the Globe's site saying the risk had been overblown.

"When I was asked by the reporter to comment on the frequency of incidents involving overheated batteries bursting into flames, I specifically stated that such incidents were extremely rare, and almost always due to battery abuse," she wrote.

When I called Nazar to confirm that she was the one who wrote the comment, she was reluctant to speak to the media again about the chemistry of lithium-ion batteries, the type used in laptops and many cellphones as well.

She did talk a bit about the new, safer batteries she mentioned in her post. Such batteries are not yet widely available for laptops, but could be in a year, she said.

However, manufacturers may not consider it worthwhile to make the switch.

"Frankly, the laptop concern … has been sufficiently low that I'm not sure that these new materials will be used in laptop batteries, because they don't have quite the same capacity as current materials," she said.

Sky-high fears

The original report on the Japan laptop fire suggests, "It is only a matter of time until such an incident breaks out on a plane." This is a fear echoed by many bloggers reacting to the photos, although it raises the question of whether, of all the components on a passenger jet, the laptop is the most dangerous.

But laptops don't have to catch fire to make news. Just getting hot is enough, especially if fertility is invovled.

When Apple introduced its MacBook computers this year, there was a lot of concern online about how hot they were getting.

Some laptop owners found that a piece of plastic was blocking the vent at the rear of the computer. Another opened up his Mac and, he said, found that the thermal grease, intended to conduct excess heat away, hadn't been applied properly.

The user manual (PDF file) for the Apple laptop does warn that it may get too hot to put on carpet, a pillow or, of all things, your lap:

Do not leave the bottom of your MacBook Pro in contact with your lap or any surface of your body for extended periods. Prolonged contact with your body could cause discomfort and potentially a burn.

Do not place your MacBook Pro on a pillow or other soft material when it is on, as the material can block the airflow vents, in particular the rear vents, and cause the computer to overheat.

More features, more heat

The problem is hardly unique to Apple laptops, though. Dell, Hewlett-Packard and Apple have all recently recalled thousands of batteries for overheating and electrical shorts. And it's possible to find complaints of overheating laptops for just about every manufacturer.

Laptops are getting more compact, meaning there's less room for ventilation to disperse heat. They're getting more features, such as DVD players, that generate more heat. And they're getting more popular, meaning more people are using them as a primary computer.

According to some research, laptops have been outselling desktops in the U.S. for about a year now. Last week, British computer retailer PC World said the same is now true in the U.K.

In Canada, the ratio of laptop computers being sold is smaller, but growing. Market research firm IDC Canada says 35 per cent of computers sold in the last quarter of 2005 were laptops, but projected that would break 40 per cent this year.