Today's average woman uses an estimated 12,000 tampons in her lifetime, a convenience that allows an unprecedented freedom to be active and confident in avoiding embarrassing leaks. We've come a long way since rags pinned into undergarments or belted-on bulky pads were the norm, but with our freedom comes risk.

There are potential problems attached to tampon use that every consumer should know about: Chlorine-bleached products, as some tampons are, contain traces of carcinogenic dioxins. Highly absorbent tampons may still cause toxic shock syndrome, a potentially fatal bacterial infection that occurs when tampons are worn for too long. There are even environmental ramifications, including pesticides sprayed on cotton crops and pollution created when tampon ingredients are bleached.

But there are safe and ecological tampon alternatives that enable women to still benefit from their use. Here, natural is the rule of thumb. "Plainer is just better when it comes to tampons," says Pam Chandler, a family nurse practitioner and certified nurse midwife who practices at the holistic clinic Wellspring for Women in Boulder, Colo. Chandler encourages patients to use nonchlorine-bleached, 100 percent-organic cotton tampons and pads. "We're lucky to have healthier choices," she says.

Dioxin dilemma

The most urgent tampon health concern is that chlorine-bleached and rayon-containing products carry trace amounts of dioxin, an extremely toxic chemical that is associated with cancer of the stomach, sinus lining, liver and lymph system. Many people are familiar with the danger of dioxins from publicity about Agent Orange and the Love Canal catastrophe.

Tampons are linked to carcinogenic dioxin formed during the bleaching process that manufacturers use to purify and whiten both raw cotton and the wood pulp that goes into synthetic fibers such as rayon, a common fiber in tampons. "You find trace amounts of dioxin in some tampons, which have maximal contact with the vagina's mucous membrane, which absorbs substances directly into the bloodstream," explains Philip Tierno, MD, director of clinical microbiology and immunology at New York University Medical Center.

How to avoid dioxin

To ensure that your tampon is free of dioxin, switch to a brand that's nonchlorine-bleached, rayon-free, and made of 100 percent-organic cotton. Though cotton is a natural fiber, the majority of cotton crops are heavily treated with insecticides, pesticides and herbicides. Organically grown cotton is not.

Check your tampon box for a list of ingredients. Whereas natural brands state that they're nonchlorine bleached, some conventional brands mention little on the subject, because along with the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA), they believe chlorine-dioxide bleaching is safe.

Tierno disagrees: While trace quantities of dioxin aren't in and of themselves a problem, tampons aren't your only exposure. "The problem is that measurable amounts of dioxins are everywhere, including food and water. Some portion of the dioxin that enters your bloodstream lodges in the body's fat cells and stays there a long time," he says. "This residual effect becomes progressively larger as you're exposed to even more dioxins."

The only way to avoid vaginally absorbed dioxin, Tierno says, is to eliminate chlorine-bleached and rayon-containing tampons and switch to peroxide-bleached products instead. Tierno also says if the label on your tampon box doesn't say "nonchlorine-bleached," it's possible that it contains chlorine. Most manufacturers proudly promote the fact that their product doesn't contain chlorine.

Dioxin's risks

The cumulative risks of dioxin are unknown. While a single tampon may contain only 0.1 parts per trillion of dioxin, the fact that most women use between 10,000 and 15,000 tampons in a lifetime increases the exposure.

"A trace quantity of dioxin is not acceptable in a tampon, because a woman does not expose herself to a single tampon," Tierno says. "It's trace quantity upon trace quantity upon trace quantity, multiplied by the number of tampons per month, multiplied by the number of months in a year, multiplied by 40 years of menstruation. Then add in all the dioxins you get from your diet, plus all the ones occurring in the environment."

Earth-friendly tampon options

The environmental impact of the manufacturing of feminine products is another reason to use organic tampons. While cotton tampons may seem better than synthetic, most cotton undergoes industrial bleaching in a polluting process that dumps dioxins, along with other hazardous organochlorines, into the water supply.

Organic cotton tampons and pads are treated with hydrogen peroxide instead of bleach, making them a safer alternative. If the label states that the product is third-party certified organic, that means the cotton has been grown without pesticides on land where no pesticides have been applied for at least three years.

In response to concerns over dioxin in tampons and their impact on the environment, the EPA and some manufacturers have worked to find a better way of purifying wood pulp and cotton without creating dioxins. The result is chlorine-dioxide bleaching, a process that has replaced the elemental chlorine-gas method of the past but still generates low trace levels of dioxins.

The packaging of tampons is another troublesome environmental issue. Most are encased in a paper or cellophane wrapper, contain a cardboard or plastic applicator, and are packed in boxes. Though you can't recycle cotton tampons, there are waste-saving alternatives to dealing with menstruation, such as washable natural sponge tampons and cloth pads, and reusable, but awkward, vaginally inserted menstrual cups that collect flow.

Toxic Shock still a risk

In the '70s and '80s, toxic shock syndrome (TSS) struck thousands of women. The crisis peaked in 1980 with 814 cases of TSS, of which 38 women died, most due to extended use of the high-absorbency Rely tampon. Today, women still get TSS, though cases are rarely publicized.

Yet tampon safety is once again a national issue, in part due to the efforts of Rep. Carolyn Maloney, D-N.Y., who introduced a bill to address the health problems associated with tampon use. The Robin Danielson Act (HR 360) is named after a 44-year-old woman who died in 1998 from TSS because she didn't recognize her symptoms. The bill directs the National Institutes of Health to conduct reliable, independent research to determine the health risks posed by the presence of synthetic fibers, dioxin and other additives in tampons.

What causes Toxic Shock Syndrome?

TSS is caused when staph or strep bacteria grow in the vagina, usually encouraged by the presence of a higher absorbency tampon or one that has been inserted more than eight hours. The bacteria produce toxins that are absorbed into the bloodstream, which can cause a severe drop in blood pressure (shock) and/or organ failure, especially of the liver and kidneys.

In some cases, TSS is fatal. Its symptoms are similar to the flu, including a high fever, vomiting and diarrhea, muscle aches, dizziness or fainting, a red rash, headaches, bloodshot eyes and sore throat.

"Highly absorbent tampons, especially those containing synthetic fibers, increase the amounts of toxin present in the vagina," says Tierno.

In the mid-'70s, synthetic fibers were used in tampons because manufacturers wanted to produce more absorbent, leak-resistant products. Since then, three of the four problematic synthetics have been eliminated from tampons. "The only one left is viscose rayon," Tierno says.

How to reduce your risk of TSS

To minimize your risk of contracting TSS, choose a tampon made of 100 percent cotton, preferably organic. "You're at the lowest risk possible with cotton," says Tierno. "In my research, every synthetic fiber amplified toxin development, whereas cotton did not."

Most precautions for guarding against TSS are simple, says holistic nurse practitioner Pam Chandler, a specialist in women's health care. Wear a tampon for a maximum of six to eight hours to avoid bacterial growth. However, she recommends leaving it in for at least two hours.

"If you remove a tampon too soon, it won't be saturated," she says. "Then you risk scraping the dry, fragmented cotton across the vaginal mucosa, irritating it and setting the scenario for infection." Also, using a tampon overnight, when planning to sleep longer than eight hours, is risky. At night, consider wearing a pad instead, she advises.

Choosing a tampon with proper absorbency is crucial to preventing TSS. "At the beginning of your period, if your flow is heavy, you may need Super Absorbency so you don't have to change tampons too often," says Chandler. When the flow slows, however, don't be tempted to continue with a Super because it's more convenient. Switch to a lower absorbency tampon instead. Also, use tampons only during menstruation.

Deodorized or fragranced tampons

Within the last couple of years, a rash of e-mails warned women that tampon manufacturers put asbestos in their tampons to make women bleed more in hopes of selling more product. Tierno says the rumor was false. "I have been privy to every manufacturer's records over the last 21 years, and I have never seen anything related to asbestos in tampons," he says.

Though the asbestos scare amounted to nothing but an urban myth, true additives to be concerned about are fragrances and deodorants. Perfumes may mask odors, but some women suffer allergic reactions to them. "Without question, a deodorized tampon is dangerous," asserts Tierno, adding that deodorants encourage overgrowth of certain bacteria, upset the vagina's normal flora and irritate the mucous membrane.

The main point, when it comes to tampon use, is to stay informed and weigh the options. "Over the years, tampons have allowed women to be more active and fuss less during their periods," says Chandler, who points out that while this is liberating, it also makes it easy to take their use for granted.

Laurel Kallenbach writes about natural health, travel and the arts.