The people of Toledo, Ohio, were finally given the green light to turn on their taps and use the water today for the first time in more than 50 hours after a massive toxic algae bloom on Lake Erie forced a drinking ban in the state's northwest corner.

"My appreciation of water has gone up tenfold," resident Becky Haslinger said. "I had no idea how much I was using."

The state of emergency had been in place since Saturday for Toledo, where nearly 400,000 residents rushed to stock up on bottled water.

On Friday, routine water testing showed the city's water supply had been contaminated by toxins.

A toxic algae bloom, blamed on runoff from farmlands that then contaminated the water supply, was the suspected source.

"It's being caused by farm runoff [and] human sewage that's being released by storm waters from cities," said Frank Szollosi of the National Wildlife Federation.

The thick, green sludge - the suspected source of toxins in the water - could even be seen from space. Restaurants, shops and schools were closed up.

Today, the mayor of the state's fourth-largest city lifted the ban, announcing that the water was safe and that the results of six tests had come back with no problems.

"Our water is safe," said Mayor D. Michael Collins, who then drank a glass of water in front of reporters. "I'm pretty thirsty right now [because] it's been a long night."

Other cities on the Great Lakes like Detroit, Michigan; Cleveland, Ohio; and Buffalo, N.Y., said they were monitoring the drinking supply. The Great Lakes supply drinking water to about 26 million people.

The Environmental Protection Agency said experts in 40 states had reported outbreaks of toxic algae.

Experts said new farming techniques were needed to help keep fertilizer on the fields from spilling into water supplies.