Summertime, and the living is dangerous.

The great outdoors tempts tan-seekers to abuse their skin in the sun. It pulls people out of their depth in cool water, brings on overheating in long distance runners and bikers, and subjects various parts of your body to injury from unaccustomed kinds of work and play.

Chances are, you already know the common sense summer safety tips:

* Sun-worshipers need sunscreen to protect against skin cancer and sunglasses with ultraviolet filters to protect against cataracts.

* Mad dogs might go out in the midday sun, but road and court exercisers should do their thing either early in the morning or late in the afternoon.

* Bikers need helmets, swimmers need lifeguards, boaters need life jackets and fireworks need to be left to the professionals and enjoyed from far away.

But did you know that people who mow lawns need protective footwear?

Bare and sneakered feet are vulnerable to mower blades, so it's better to mow in hiking boots or golf shoes, says Dr. Mark Myerson, director of Union Memorial Hospital's Foot and Ankle Service.

And did you know you need protective eyewear when doing projects around the house or fixing your car?

"There's rust and dirt under the car," says Dr. Terrence O'Brien, director of the ocular trauma service at Johns Hopkins Hospital. "Any time you're underneath the car to change the oil or work on the muffler, and you're looking up, it is just inviting danger; gravity will send stuff into the eyes."

And you don't have to be lying down to endanger your eyes.

"When you're trying to build a patio or deck and working with hammer and nails, friction is created and little shavings of the metal can become projectiles," says Dr. O'Brien. "When you're using power tools, a tiny piece of metal can hit the eye with the velocity of a missile."

So can a baseball (players should wear face shields, he says) or a golf ball (when someone yells "Fore!" cover your head and duck; don't look up).

Hardware stores, sporting goods stores and eyeglass stores carry protective eyewear; weekend warriors should stop and shop before they head out to conquer the yard, the car or the playing field.

People also should stop and think safety before they try to conquer the ocean, pool or river.

"If you look at the drowning statistics, in one-half to two-thirds of situations people are swimming alone, or they never intended to get into the water -- they were fishing, boating, working or walking near the water, and had never learned to swim," says Scott Knox, director of the Red Cross district offices in Howard and Carroll counties.

So, first of all, you should learn to swim; and you should only do it where there's a guard on duty, and you should always wear your life jacket or flotation device when you're boating. If, for any reason, you're in a fast-moving current, don't fight it, Mr. Knox advises: "Try to relax, and let it take you to some place where the rTC water is more still, or try to swim diagonally against it."

Public pools are safer. But even your tiny backyard wading pool can be hazardous if a tiny child is left alone in it: kids can drown in a couple inches of water. If you've got a bigger, permanent pool, you have to have barriers all around it -- "and if one of the barriers is your house itself, be sure the doors are locked so a child cannot go out without an adult," Mr. Knox warns.

And, he adds, "In most backyard pools, diving should be off-limits. Most of the severe spinal injuries around water are the result of diving into 5 feet or less, but sometimes it can happen in 6 or 7 feet of water,too."

Also off-limits, now and forever according to experts, is the great American suntan.

Skin cancer has been linked to repeated sun exposure over time, and melanomas are associated with a blistering sunburn. One blistering burn doubles your lifetime chance of getting melanoma, according to Dr. Linda Lutz, assistant professor of dermatology at the University of Maryland School of Medicine.

But that doesn't mean beach bunnies have to live indoors; they just have to be careful. "I recommend sunscreen for everyone, from May to December," Dr. Lutz says. "I don't think anything less than a No. 15 is worth anything, and it is usually not necessary to use anything greater than 15, except for someone on medication like tetracycline, and for people who are very fair."

The SPF (sun protection factor) number describes your safe sun time: No. 15 protects you from overexposure for 15 times as many minutes as you'd have without anything. For most people, that adds up to several hours -- as long as what you're using has some staying power. Look for something sweat- and waterproof. And wear it whenever you're outdoors; you don't have to be by the waterside to get a sunburn.

"The majority of sun damage is done by age 20," adds Dr. Lutz, which makes sun-screening especially important for youngsters. The preparations now on the market, however, have not been tested on anyone younger than six months of age; therefore, she advises keeping babies safe by covering them with clothing and shading them with umbrellas if you have to take them out in the sun.

Babies in bike-seats should be protected by a biker's helmet, says Steve Purvis, marketing director at the League of American Wheelmen in Baltimore. And to make sure motorists know there's a baby aboard, the baby bike-seat should be in a bright or fluorescent color, with an orange flag attached, he says.

If riding a bike at night, he adds, use a headlamp and taillight, and reflective bracelets, vest or cross belt. And if you're riding all day, or for a good part of it, take some food and fluid along with you. "Always drink before you're thirsty and eat before you're hungry," he advises.

What you drink can be as cheap and easy to get as tap water; sports drinks give you extra potassium that you don't need if you're getting a balanced diet, and extra sodium when you're probably ingesting too much of it anyway.

Whatever your activity, you should take in fluid all day long -- before you work out as well as after, whether you feel you need it or not.

"Swimmers need fluid replacement, too," adds Diane Corbett, certified athletic trainer at Essex Community College and Greater Baltimore Sports Medicine and Rehabilitation Center. "You don't feel the sweat on your body while you're in the water, but if you're doing an activity like swimming laps, you're going to be sweating."

Avoiding eye injuries

Although a lot of accidents can be prevented, bad things still happen to careful people. "Some things are hard to predict; freak accidents do occur," says Dr. Terrence O'Brien, director of the ocular trauma service at Johns Hopkins Hospital.

"Usually, it happens in a split second: someone does something without thinking, and there's a potentially blinding injury," he adds.

Some quick thinking in the split seconds afterward might lessen the damage, however.

If a caustic chemical has splashed in the eyes, get it washed out fast. "You don't even have to have totally clean water. Get to a sink, a hose, use soda pop or bottled water or any source of non-caustic liquid. Then go to the emergency room," Dr. O'Brien says.

If a sharp object or rust gets in the eye, don't try to take it out, he warns. "Don't rub to remove foreign bodies. If something is embedded in the eye, cover it and come right into the emergency room."