ST. LOUIS (AP) — Leaders of companies in Ohio and Missouri have pleaded guilty to illegally shipping 9 million pounds of hazardous waste from Mississippi to Missouri.

Prosecutors say Raymond Williams and his company, U.S. Technology Corp., pleaded guilty Tuesday in federal court to conspiring to transport hazardous waste. Williams, of Atlanta, is the sole shareholder and director of U.S. Technology, which was based in Canton, Ohio.

Daryl and Penny Duncan, of Chicago, both pleaded guilty Thursday to placing a person in imminent danger by releasing hazardous waste into the air, misdemeanor. They owned a company called Missouri Green Materials in Berger, Missouri, that accepted the waste from Williams’ company in 2013.

Prosecutors say neither company nor their officers obtained the permits needed to ship or dispose of the waste.