Gov. Chris Gregoire has signed into law a bill to limit the use of phosphorus-based fertilizers in an effort to protect water sources from contamination.
Supporters say that runoff from the widely used fertilizers has contaminated lakes and streams and contributed to harmful algae blooms.
The bill, which takes effect in 2013, makes an exemption for phosphorus-based fertilizers being used on gardens or agricultural lands. Retailers still may sell products that are specifically labeled for one of the permitted uses.
The "Healthy Lawns, Clean Water" bill was one of the top four legislative priorities for the Washington Environmental Priorities Coalition this year.
Democrat Rep. Andy Billig of Spokane, the bill's main sponsor, called Thursday's signing a "giant step forward for clean water."