I pulled the car into the garage of the large tire and repair center for a now-defunct department store chain. As I got out and walked to the front of the Cadillac to open the hood. As the hood came up I looked to the battery but didn’t quite see what I expected to see. The entire top of the battery was gone. The shattered tops of lead plates were lined up like injured soldiers trying to stand in ranks for inspection.

As I noticed the condition of the battery, out of the corner of my eye, I saw a tall man of about 60 with white hair and a weathered face stepping up beside me. It was obvious that he was the owner of the car. I looked to him and noticed rivulets of blood dripping down his face.

It turned out that he was a Good Samaritan who was helping someone out in the Old Orchard Shopping Center in Skokie, where the tire and repair center was located. Someone had asked him if he could help jumpstart their car. He agreed and got his jumper cables out of his trunk.

He attached the positive (red) cable to the positive battery post, and the negative (black) cable to the negative post on the other person’s dead battery. So far, no problem.

Then he took the other ends of the cables over to the good battery in his Cadillac and did the same thing. When he connected the negative cable there was a spark and an explosion. He was very fortunate that the explosion didn’t get his eyes.

What happened is that there are gasses emitted by the batteries (this story is from 1974 – newer batteries are sealed but can still represent an explosion hazard if jumpstarted improperly). When he connected the black-negative cable to his battery there was a spark. It ignited the fumes above the battery.

The way to avoid the hazard is to go ahead and hook the positive (+) and negative (-) cables to one battery. When you connect to the other battery, however, go ahead and connect the positive cable to the positive side of the battery. But, instead of connecting the negative cable to the negative post of the battery, connect it to a ground (a metal part) of the engine.

Exploding batteries are, thankfully, very uncommon. You can avoid this risk with your own vehicle by having your battery and charging system checked. This is especially important with the approach of winter. The cold thickens the oil in your engine making it more difficult for the lubricant to work its way up from the oil pan to reduce the friction between moving parts of the engine.

Of course, if you’re a Good Samaritan and help someone whose car needs a jumpstart, make sure you hook up the jumper cables safely.