Rockford Lake in Holmesville may look peaceful and inviting, but the health department says there's something dangerous lurking beneath the surface.

The Nebraska Department of Health and Human Services declared the first algae-related health alert of the season, citing an excess of toxins from blue-green algae in the lake.

Dave Tunink of the State Game and Parks Commission says people can still camp, fish, and boat on the popular lake near Beatrice, but must avoid ingesting the water, because it could make them sick causing vomiting, diarrhea, respiratory failure, and rarely, even death.

"Cyanobacteria or blue-green algae has the ability to produce toxins that release into the water, which can be harmful to various animals and humans in various forms," said Tunink.

Tadd Barrow works to educate people on water quality through the University of Nebraska-Lincoln. He says the common algae you might find stuck to a rock or your fishing line isn't what you should be worried about; blue-green algae is harder to see and stays floating in the water.

"What we're concerned with is the type of algae that looks like somebody dumped a bucket of green paint on the surface of the water. It's very liquid-like. And what I tell people is if you're concerned between the difference, take a stick, go down and try to pick it up, you cannot pick up the toxic algae, it will make the stick wet," said Barrow.

Barrow also says algae flourishes with an excess of nutrients in the water, which can be expensive to treat.

"There are ways to treat lakes for algae and many private lake associations are doing that; there are some major costs associated with that," Barrow said.

So without the resources to treat the water, the health department says it's just too dangerous to swim.

The State Game and Parks Commission says it's still safe to fish, and there's no indication that eating the fish fillets is dangerous, but Tunink says he would avoid eating fish organs because they could store up the toxins.

Also, if you come into contact with the water, Barrow says it's important to wash that area of your skin, and keep an eye on it for any rashes.

Barrow says if you're worried about algae in a body of water on your property, you can go to the website below to learn more about a free test they'll perform for you.

Also, to monitor the health alerts in lakes throughout the season, just click on the Nebraska Department of Environmental Quality link below.