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...