Wichita ? Five Kansas cities and a rural water district have signed onto a lawsuit against the maker of the weed killer atrazine.

The Wichita Eagle reported that the Kansas plaintiffs are Marion, Dodge City, Plains, Carbondale, Oswego and the Miami County Rural Water District No. 2. They are among 16 water systems in six states asking Syngenta for more than $75,000 each to cover the expense of treating water for atrazine.

Atrazine is a popular herbicide that has been used to kill grasses and broadleaf weeds for decades. Its levels tend to spike as atrazine-containing herbicides are applied during the spring planting season.

The lawsuit — filed in March in U.S. District Court in southern Illinois — claims atrazine exposure has been linked to birth defects, low birth weights and premature births.