The Ohio state Legislature has passed bills to try to cut down on the nutrients flowing into Lake Erie that feed cyanobacteria.
Cyanobacteria looks like algae, and some forms are toxic.
A cyanobacteria bloom shut down Toledo's water supply briefly last summer.
Manure, untreated sewage, sediment, and phosphorus all encourage the growth of cyanobacteria.
The legislation establishes fines against farmers caught applying manure on a frozen field or right before a heavy rain.
Wastewater treatment plants will have to start testing for phosphorus.
Officials will also have five years to find a different place to dump harbor sediment than in Lake Erie.
The National Wildlife Federation says the bills are a good first step, but they will not reduce phosphorus levels in Lake Erie by 40%, which the group says is the level of reduction needed to control cyanobacteria.