Vog exposure: The volcanic haze dubbed vog is caused by gases released when molten lava -- from the continuous eruption of Kilauea volcano on the Big Island -- pours into the ocean. The winds then put up the "vog" and carry it around the islands. So yes, even though you are on Kauai, there can be some "vog" days. Some people claim that long-term exposure to the hazy, smoglike air has caused bronchial ailments, but it's highly unlikely to cause you any harm in the course of your visit.

There actually is a vog season in Hawaii during the fall and winter months, when the trade winds that blow the fumes out to sea die down.

Don't Feel the Burn: Smart Tanning Tips

Hawaii's Caucasian population has the highest incidence of malignant melanoma (deadly skin cancer) in the world. And nobody is completely safe from the sun's harmful rays -- all skin types and races can burn. To ensure that your vacation won't be ruined by a painful sunburn, be sure to wear a strong sunscreen that protects against both UVA and UVB rays at all times (look for zinc oxide, benzophenone, oxybenzone, sulisobenzone, titanium dioxide, or avobenzone in the list of ingredients). Wear a wide-brimmed hat and sunglasses. Keep infants under 6 months out of the sun completely, and slather older babies and children with strong sunscreen frequently.

If you do get a burn, aloe vera, cool compresses, cold baths, and benzocaine can help with the pain. Stay out of the sun until the burn is completely gone.

Shark Safety

Note that sharks are not a big problem in Hawaii; in fact, they appear so infrequently that locals look forward to seeing them. Since records have been kept starting in 1779, there have been only about 100 shark attacks in Hawaii, of which 40% have been fatal. Most attacks occurred after someone fell into the ocean from the shore or from a boat; in these cases, the sharks probably attacked after the person was dead. But general rules for avoiding sharks are as follows: Don't swim at sunrise, at sunset, or where the water is murky due to stream runoff -- sharks may mistake you for one of their usual meals. And don't swim where there are bloody fish in the water, as sharks become aggressive around blood. For more on sharks, see the Hawaii State Department of Land and Natural Resources info at www.hawaiisharks.com.

Stings

The most common stings in Hawaii come from jellyfish, particularly Portuguese man-of-war and box jellyfish. Because the poisons they inject are very different, you need to treat each type of sting differently.

A bluish-purple floating bubble with a long tail, the Portuguese man-of-war is responsible for some 6,500 stings a year on Oahu alone. These stings, although painful and a nuisance, are rarely harmful; fewer than 1 in 1,000 requires medical treatment. The best prevention is to watch for these floating bubbles as you snorkel (look for the hanging tentacles below the surface). Get out of the water if anyone near you spots these jellyfish.

Reactions to stings range from mild burning and reddening to severe welts and blisters. All Stings Considered recommends the following treatment. First, pick off any visible tentacles with a gloved hand, a stick, or anything handy; then rinse the sting with salt- or fresh water, and apply ice to prevent swelling and to help control pain. Avoid folk remedies, such as vinegar, baking soda, or urinating on the wound, which may actually cause further damage. Most Portuguese man-of-war stings will disappear by themselves within 15 to 20 minutes if you do nothing at all to treat them. Still, be sure to see a doctor if pain persists or a rash or other symptoms develop.

Transparent, square-shaped box jellyfish are nearly impossible to see in the water. Fortunately, they seem to follow a monthly cycle. Eight to ten days after the full moon they appear in the waters on the leeward side of each island and hang around for about 3 days. Also, they seem to sting more in the morning hours, when they're on or near the surface.

The stings can cause anything from no visible marks to hivelike welts, blisters, and pain lasting from 10 minutes to 8 hours. All Stings Considered recommends the following treatment. First, pour regular household vinegar on the sting; this will stop additional burning. Do not rub the area. Pick off any vinegar-soaked tentacles with a stick. For pain, apply an ice pack. Seek additional medical treatment if you experience shortness of breath, weakness, palpitations, muscle cramps, or any other severe symptoms. Most box jellyfish stings disappear by themselves without any treatment.

All Stings Considered: Ocean safety -- Because most travelers to Hawaii are unfamiliar with the ocean environment, they're often unaware of the natural hazards it holds. With just a few precautions, your ocean experience can be a safe and happy one. An excellent book is All Stings Considered: First Aid and Medical Treatment of Hawaii's Marine Injuries, by Craig Thomas and Susan Scott (University of Hawaii Press, 1997).

Punctures

Most sea-related punctures come from stepping on or brushing against the needlelike spines of sea urchins (known locally as wana). Be careful when you're in the water; don't put your foot down (even if you have booties or fins on) if you can't clearly see the bottom. Waves can push you into wana in a surge zone in shallow water. The spines can even puncture a wet suit.

A sea urchin puncture can result in burning, aching, swelling, and discoloration (black or purple) around the area where the spines entered your skin. The best thing to do is to pull any protruding spines out. The body will absorb the spines within 24 hours to 3 weeks, or the remainder of the spines will work themselves out. Again, contrary to popular wisdom, do not urinate or pour vinegar on the embedded spines -- this will not help.

Cuts

All cuts obtained in the marine environment must be taken seriously because the high level of bacteria present in the water can quickly cause the cut to become infected. The best way to prevent cuts is to wear a wet suit, gloves, and reef shoes. Never touch coral; not only can you get cut, but you can also damage a living organism that took decades to grow.

The symptoms of a coral cut can range from a slight scratch to severe welts and blisters. All Stings Considered recommends gently pulling the edges of the skin open and removing any embedded coral or grains of sand with tweezers. Next, scrub the cut well with fresh water. If pressing a clean cloth against the wound doesn't stop the bleeding, or the edges of the injury are jagged or gaping, seek medical treatment.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.