California Oilwell (image) Duke University Share Print E-Mail Caption Many farm fields in the Cawelo Water District of California have been irrigated with reused oilfield water mixed with surface water for 25 years. A new Duke-led study finds the practice poses no major health risks. Credit Avner Vengosh, Duke University Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.