I have been teaching my students to light their torches with disposable lighters for many years. Periodically, one of them tells me how dangerous this practice is. They usually claim to know someone who knows someone who has had one blow up in their hand. Often the story tells of terrible injury being done to the victim. I have always been of the opinion that this is purely urban legend. None of the storytellers could ever claim to actually know someone who had had this happen. I, and several of my daring students (they hid behind a car) decided to test this hypothesis. I rigged up a 2x4 with a lighter taped to the end and lit a torch and placed it on the ground. I used a bucket as a fulcrum to swivel the lighter into the flame of the torch.

The first trial was with a cheap disposable that you might buy at a convenience store or Wal-Mart. It took about 10 seconds for the flame to melt the outer casing, and most of the gas inside sprayed out without igniting. It did not explode.

We decided to try the same variety of lighter a second time to check our results. The second lighter's gas did catch flame, and it burned up quickly, but there was no explosion. At worst, it would have startled the person holding it into dropping the lighter.

Finally, we decided to try a common Bic lighter. When the flame was applied this time, it took about 40 to 50 seconds for it to melt through the plastic to the gas. The gas ignited quickly without exploding. The interesting thing about this trial was that the plastic case fell to the ground and burned for about 20 minutes in a really strange manner. It bubbled and boiled, but the flame was barely visible.

Here are some photos from the test:

Test: Are disposable lighters likely to blow up if ignited by a torch?

Conclusion: *Probably not.

*Using a lighter or a torch or any device that produces flame can be dangerous if handled unsafely. This test in no way guarantees that a lighter couldn't explode under certain conditions. It was merely a test to see if it is likely. This test also did not include all makes of lighters. Other brands of lighters could possibly react differently. Please take every precaution to never risk your health when using a torch. Do not attempt this test yourself.