Water contamination: An article in the Nov. 15 Section A about groundwater contamination in Hinkley in San Bernardino County referred to the substance involved, hexavalent chromium, as a heavy-metal isotope. Hexavalent chromium is not an isotope of chromium but a form of the element whose atoms are missing six electrons. It is found in a number of chemical compounds used for industrial purposes.
Police officer's resignation: An article in the Nov. 15 LATExtra section about a Los Angeles police officer who resigned under suspicion of improperly accessing a law enforcement database identified Kelly Chrisman, another LAPD officer who was fired for a similar offense, as a sergeant. Chrisman held the rank of police officer.