When it comes to simple comforts, a load of crisp, clean clothes ranks up there with a glass of lemonade or a bouquet of lilacs. But some consumers are increasingly wondering if the ingredients in their laundry detergents are as clean as they thought. What does science say? The research is still developing, but here we examine how to use what we do know to identify the safest detergents for both you and the environment.

How We Got Here

Although soap—which is derived from natural fats and oils—has been used for millennia to clean fabric, synthetic laundry detergents are relatively new. They were first developed in the 1930s and launched into popularity during World War II, when scientists worked to provide the military with products that could clean when used with cold water or even ocean water.

Detergents work through two primary components: the main cleaning ingredient, called a surfactant, and a builder, which makes the surfactant more effective—and usually superior to soap in terms of cleaning soiled clothes. The builders are generally mineral compounds—often containing zeolite or phosphate minerals—that soften water and prevent soap scum. Many detergents also add enzymes and synthetic brighteners and fragrances to make laundry look, feel and smell cleaner.

But is it? Some experts and consumers are concerned that the chemicals used in detergents may cause their own set of problems—and that there are many more substances mixed in than necessary. “The chemicals that actually clean your clothes are a small percentage of the formulation of most detergents,” says Alexandra Scranton, director of science and research at Women’s Voices for the Earth, a Montana-based advocacy organization that aims to create a toxic-free future. This truth leaves many consumers wondering: What are these extra ingredients? How do they impact health of both humans and the environment? And is there a better way to make laundry detergent?

What’s in Your Detergent?

The latter question is harder to answer than you might think. Unlike food companies, cleaning-product manufacturers aren’t required to disclose what’s in their products. As a result, many don’t. And there’s very little regulation regarding label claims, rendering terms like “green” or “natural” or “biodegradable” nearly irrelevant. So how can you tell what you’re getting?

Scranton offers a few suggestions. First, seek out companies—such as Seventh Generation—that are disclosing ingredients. “That’s a very important sign that companies are paying attention [to health and environmental impact],” Scranton says. If you don’t see ingredients on the label, check the company’s website. “Many companies are starting to put ingredient information online,” she explains. “But if a company isn’t telling you what is in the product, don’t buy it.”

An additional strategy is to look for what’s not in the detergent—products that claim to be “fragrance-free,” for example. “Fragrance” is a catch-all term used on cleaning and personal-care product labels, referring to a cocktail of any of thousands of chemicals that lend the product its scent. A study in the Journal of Environmental Health found that “fragrance” irritated about 30 percent of the U.S. population, and caused headaches and skin or respiratory problems in around 19 percent of people. Another study, published in Air Quality, Atmosphere & Health, reported up to 25 potentially hazardous chemicals—including two known carcinogens with no established safe-exposure levels—emitted from dryer vents while running a load of laundry washed with a scented, liquid detergent and dried with a scented dryer sheet (both top-sellers in their categories). Removing the dryer sheet reduced the number to 10.

Consumers should also be wary of optical brighteners, which coat your clothes with chemicals that absorb ultraviolet and violet light and enhance blue light to make fabrics appear brighter. “The chemistry is genius—how the chemicals resist heat and water to stay on your clothes,” Scranton says. “But the chemicals that are released into the water system are terrible for fish.” They also might cause reproductive and developmental damage, according to an EPA-sponsored report, although more research is needed to know for sure.

Most fabric softeners work in the same way, Scranton says, by coating your clothes with chemicals that may be harmful to both your body and the earth.

Digging Deeper

If you’re still not sure whether a product is safe, check out the Environmental Working Group’s (EWG) Guide to Healthy Cleaning at ewg.org, which identifies potentially dangerous ingredients, helps you decode labels and rates top products. You can also look for the EPA Safer Choice label on products and buy organic, which will ensure the absence of many hazardous chemicals—and ultimately a “greener” cleaner.

What Form Is Best?

Powder? Liquid? Gel? Pods? If you have children, steer clear of pods, which many kids mistake for candy. Powder and liquids tend to be equally effective, but opting for a more concentrated product can lower the carbon footprint because it’s packing in a lot more per shipping load.

Use these detergents and laundry aids for clothes that not only feel clean, but actually are.

Seventh Generation Free & Clear Natural Laundry Detergent

An EPA Safer Choice seal and a USDA 97% Biobased Product certification enable your mind and your skin to rest at ease.

Mrs. Meyer’s Clean Day Laundry Detergent – Lemon Verbena

This fresh-scented cleaner is free of phthalates, optical brighteners and other can-do-without chemicals. Pair it with Mrs. Meyer’s Lemon Verbena Fabric Softener, which includes natural essential oils.

Method 4x Concentrated Laundry Detergent – Beach Sage

The ultra-concentrated formula means you’ll use less with each wash; plus, you’ll love the nontoxic scent.

Ecos Laundry Detergent – Lavender

This EPA Safer Choice detergent employs lavender oil to keep your clothes smelling great.

Boulder Clean Natural Laundry Detergent – Valencia Orange

Essential orange oil in this EPA Safer Choice detergent lifts greasy stains and leaves clothes smelling fresh.