Toxic chemicals and what police are calling an extensive meth lab.

That's what police say they found Wednesday morning just 300 feet from Patrick Henry Middle School in Sioux Falls. Employees from Mid-American Energy were at the house checking on a gas meter that may have been tampered with.

They noticed a suspicious smell and called police. The first officer on the scene immediately suspected it was a meth lab and called for back-up.

After getting a search warrant, drug investigators suited up and went into the house on East 31st Street with guns drawn. It didn't take them long to find the source of the odor. 

"It's pretty clear there is a fairly extensive lab in the basement," says Officer Loren McManus.