Procter & Gamble has told the Guardian that it plans to eliminate phosphates from all of its laundry detergents, including Tide, within two years.

It's a newsworthy move considering the sheer size of the company, which claims the lion's share of the North American laundry detergent market and more than 25% of the global market share.

But P&G already stopped using phosphates in laundry detergent sold across the US in the early 1990s as part of a voluntary commitment from the American Cleaning Institute, an industry group of which the company is a member. It also removed phosphates from its detergents sold in the Europe several years ago.

So the change, which has been in the works since 2005, will likely have the greatest impact on developing countries that don't have regulations limiting phosphates in detergents.

"It's a win-win when you offer consumers a better product which is also environmentally friendlier," says Giovanni Ciserani, the company's group president of global fabric and home care. "Whenever you force them into a trade-off, you get a limited result."

The problem with phosphate

The phosphate used in most powdered detergents is sodium triphosphate, or STPP, and it's used to soften hard water. But when it's introduced to waterways, phosphorous can cause environmental damage, including algae blooms, low oxygen levels and fish deaths.

These issues came to public attention in the late 1960s and early 1970s, when lakes and rivers in the US turned bright green with algae. The situation drew first alarm, then activism, as scientists identified phosphates in laundry detergent as part of the problem. Public pressure mounted to remove them. In subsequent decades, various US states – and some countries – passed regulations to limit their use. The European Union followed suit in 2013.

These regulations, plus better sewage treatment, have improved water quality in the US and many other developed countries.

A bold move, but not a new one

P&G isn't the first company to go phosphate-free. Smaller companies such as Belgium-based Ecover and US-based Seventh Generation, have been making phosphate-free laundry detergent since they were founded in 1980 and 1988, respectively.

"Saying now that you're going to be without phosphates, it's not big news to me," says Tom Domen, long-term innovation manager for Ecover.

Using zeolite, the same mineral P&G is using now, Ecover had formulated its detergent to be as effective as one containing phosphates as early as 1989, he says.

Of course, Ecover and Seventh Generation don't have the market reach of P&G. The alternative brands also aren't sold in many developing countries, which often lack regulations on phosphates, Ciserani says.

Such countries also tend to lack effective water treatment infrastructure, says Jon Scott, an editor at the US-based advocacy organization Clean Water Action. "What little there is isn't often designed to remove nutrient pollution like phosphates from the water," he says. "[So P&G's commitment] could potentially have quite a large impact."

Pricing and supply

So why is P&G doing this now?

The trigger for making this change globally – even where not legally required – was the company's recent creation of a product that is effective even in hard water areas, Ciserani says.

From a business perspective, it might not be a bad time to go phosphate-free. In recent years, the price of the commodity has increased as supplies have tightened around the world.

"They (P&G) may be doing it as much for cost of the phosphate as an additive as opposed to concern for protecting the water," Scott says.

It's certainly a step ahead of competitor Unilever, which didn't comment on whether it has plans to remove phosphates.

Instead, Unilever's press office coordinator, Andriana Matsangou, referred to the company's website, which reads: "Detergent phosphate is safe, effective and sustainable in the majority of cases. However, its use can be inappropriate in some specific areas...." It goes on to say that phosphates sourcing results in higher greenhouse gas emissions than alternatives, according to recent data, and that Unilever is "working to substitute them with alternatives where possible".

The scale of the problem

Detergent is not the only source of phosphorous in ecosystems, which occurs naturally in some soil and rocks. Other key human sources are sewage, animal waste and fertilizer runoff from agricultural and lawns.

The percentage that comes from detergents varies. Prior to the introduction of phosphate-free products, household detergents accounted for almost half of the phosphorous load in European waters, according to the European Water Association, a group of water industry professionals.

Phosphates remain in dishwasher detergent in many areas, largely due to the more recent introduction of dishwashers into homes. In the US, the American Cleaning Institute announced a voluntary ban in 2010, and the EU plans to legislate a ban starting in 2017.

Ciserani says P&G will comply with any regulations on dishwasher soap and will proactively remove phosphates from dishwasher detergent when it has created a superior alternative.

"It's always good news when a manufacturer decides to take steps that prevent pollution at the upstream end of things," Scott says.

But he cautioned that other detergent ingredients – including dyes, whiteners, and fragrances, the latter of which often contain phthalates – haven't received much study and could also harm human health or the environment.

He commended Seventh Generation for avoiding these ingredients and for introducing a recycled paperboard container for its liquid detergent. Sustainability requires considering the whole lifecycle of the product, he says.

Erica Gies is an independent reporter who covers water and energy for The New York Times, The Economist, Scientific American, and other publications.