LIME SPRINGS, Iowa (AP) — Some northern Iowa residents have banded together to fight what they call pollution of their water and air after several failed attempts to thwart the rise of hog confinements. The Waterloo-Cedar Falls Courier reports that the Northeast Iowans for Clean Air and Water has organized an agreement with Howard County residents to form a covenant not allowing manure to be placed on their land. Manure becomes more toxic with a large number of hog confinements.

The covenant is comprised of about 43 families, with 63 separate properties between four townships. The properties together span more than 5,500 acres. The Iowa State University College of Veterinary Medicine says swine manure can generate toxic chemicals, including ammonia, hydrogen sulfide, carbon monoxide, carbon dioxide and methane.