A great deal of progress has been made on the clean up.
Here's a little on what happened and where they are in the investigation.
The Federal Railroad Administration is investigating the derailment, but the agency has not offered any clues into the cause. An agency spokesman said earlier this week that it could take up to a year before the agency releases its findings and probable cause.
Officials said 16 cars derailed. Three of the tank cars were found to be leaking, including 750 gallons of the liquid contents of a tanker containing sodium hydroxide, a chemical which CSX said is used to produce various household products, including paper, soap and detergents. Another car leaked ethanol and another calcium chloride. All the leaks were contained Sunday, officials said.
Officials said air testings have shown “no adverse effects to air quality,” officials said.
CSX Transportation said workers have removed five damaged cars from the site; 11 cars remain at the site and will be taken away when the tracks are restored. Crews also completed excavation of the soil impacted by the sodium hydroxide leak and are refilling the area with new soil. After this process, CSX will rebuild the damaged tracks and restore service.