New York’s Metropolitan Transport Authority has launched a pilot program to get female rats in Manhattan on birth control. Officials teamed with SenesTech in Flafstaff, Arizona, to test ContraPest, a product that, when consumed by rats, promotes egg loss and can cause infertility in days.

According to Bloomberg Businessweek, ContraPest is made up of mostly salt, sugar, fat and two active ingredients — an industrial chemical and an herb. The goal is to reduce the current rat population by 75 percent.

Rats are very fertile, they can have up to 12 baby rats per litter and as many as seven litters a year.