For many, Memorial Day’s unofficial start of summer means grilling, pool parties and kids wildly happy to be at the end of another school year.

For John Derenberg, a safety expert and dad in suburban Chicago, it’s a dangerous time for the law of unintended consequences, especially in the backyard.

The electrical engineer by training is the consumer safety director for Underwriters Laboratories, the independent, non-profit product safety testing and certification organization.

He’s not looking to kill summer fun, but he’d like you to know:

•Nearly half the 12,000-plus kids up to age 19 who die each year of unintentional injuries do so in June, July and August, according to the Centers for Disease Control and Prevention.

•Each summer, about 2.7 million children visit the ER as a result of injuries around the pool or backyard. About 200,000 children under 14 wind up in the ER for playset-related injuries every year.

•Barbecue grill fires result in about 8,000 home fires annually, according to the National Fire Protection Association.

So, whether you’re planning a staycation or an outdoor bash, exercise your safety muscles and take stock of play equipment, grills, pools and other potential hazards. Following are safety tips from UL (which is the mark you should look for, by the way, if you’d like to make sure flotation devices are worthy):

Grilling

•Charcoal can heat to a temperature of 1,000 degrees. Don’t bury embers in sand or a corner of the backyard before dousing them with a hose or buckets of water first. It’s likely people are running around barefoot.

•Yikes, it’s raining! It’s not a good idea to drag your grill into the garage or plop your hibachi in the sink. Never grill indoors or near garages or porches. In fact, stay at least 10 feet from any structures.

•Keep a spray bottle or fire extinguisher within reach. Flare-ups can’t always be anticipated. “You get a flare-up and you’re not there, your whole garage can be engulfed,” Derenberg said. “Spray at the base of the flames. It won’t ruin your food.”

•If you’ve got a new gas grill, make sure all its parts are tight. For older grills, check hoses for cracking, brittleness or leaks.

Pool safety

•Warm-weather parties can mean a dozen or more kids running around as the grown-ups gab.

Good pool supervision means scanning the area every 20 seconds when children are in the water, with an adult no more than 10 seconds away.

•Good pool supervision is not telling the 12-year-old to keep an eye on the little ones, no matter how strong a swimmer the older child might be. “Some 12-year-olds are baby sitters and some 12-year-olds need baby sitters,” Derenberg said.

•A 4-foot fence around a pool with a self-closing, self-latching gate and locks beyond a child’s reach are recommended.

To keep children from climbing, avoid stacking chairs, other furniture or pool equipment near a fence. The same goes for leaving toys in the pool that can entice kids back into the pool area after water playtime is over.

•Cover drains in pools and spas. The suction can be dangerous to children.

Playsets

•Kids grow. Play structures don’t, so take heed of older daredevils looking to climb and swing higher than the structure was built to withstand. According to the Consumer Product Safety Commission, 70 percent of all playground-related deaths occur on home playground equipment.

•Make sure equipment is anchored safely in the ground, all pieces are in good working order, S-hooks connecting chains to swings or ladders are entirely closed and all bolts are not protruding, Derenberg said.

•Lay down mulch, sand or a rubberized surface around a play structure.

If all of this feels like common sense, it should, Derenberg said, but this is the time of year when many of us are antsy and might be looking to cut corners.

“We’re in a hurry. That happens in parts of the country that have been waiting for nice weather much of the year,” he said. “All of a sudden you’re getting out the grill and the wading pool and it’s hurry up before fall.”