A rail line in eastern Iowa reopened on Saturday following a freight train derailment that sent three cars tumbling into the Mississippi River, spilling ethanol fuel in the water, Canadian Pacific Railway (CP) said. Thirteen cars and two engines went off the tracks after the derailment on Wednesday in a remote location north of Dubuque, Iowa, the company said. Three of the cars that derailed caught fire, but there were no injuries. Still, the accident could further heighten scrutiny of the safety of transporting flammable goods via rail after a series of fiery mishaps. By Saturday, all derailed cars had been removed and those carrying ethanol were sent to a staging area where they will be thoroughly cleaned to ensure no ethanol vapors remain, the company said. State and federal environmental agencies have set up 40 sites to test the river and surrounding area for ethanol contamination, CP spokesman Jeremy Berry said in a statement. It was unclear how much ethanol leaked following the derailment, but some fuel had pooled on the frozen river and riverbank, the Iowa Department of Natural Resources said. Spilled ethanol fuel will mix with water and in high enough concentrations can deplete oxygen and kill fish and plants. So far, two testing areas on the riverbank displayed barely detectable levels of ethanol, the company said. No other monitoring sites detected the presence of any ethanol. The company said it has also set up a restoration and remediation plan to minimize the environmental impact of the spill and to continue to monitor for the presence of ethanol in the water, as well as the level of dissolved oxygen.