Washington DC chemical leak after CSX freight train derails

<h>Fourteen wagons of the CSX freight train overturned near
Rhode Island metro station early on Sunday<h>
Sodium hydroxide, a form of caustic soda, leaked from one
wagon, which was later sealed by emergency crews.
Crews also plugged a leak in another wagon after a release of
non-hazardous calcium chloride.
The cause of the derailment is unclear.
Sodium hydroxide is a corrosive chemical that can irritate and
burn the skin and eyes.
According to the US Centers for Disease Control, while
sodium hydroxide is not combustible, contact with moisture or
water may generate enough heat to ignite combustible
substances.
"We don't know how much leaked," District of Columbia Fire
Department Deputy Chief John Donnelly was quoted as saying
by Reuters news agency.
"The fumes should not cause you any problems."
CSX said the train had three locomotives and a total of 175
cars - nearly half of them empty, the rest carrying mixed
freight.