Contact Us Gateway Drug Screening Gateway Drug Screening 206 South Church Street Union, Missouri 63084 Toll-Free: 888-770-7311 Office: 636-583-2055 Mobile: Fax: 888-676-6816 Hours of Operation: 9am - 5pm Monday - Friday info@GatewayDSI.com Your Name (required) Your Email (required) Subject Your Message Are You Human? 36 / 9 = ?