Updated Tuesday, March 25 at 1:15 p.m.:
Test results from sampling conducted by the National Guard in and around West Virginia American Water's Elk River plant indicate trace levels of MCHM are being added to the water supply during the filtering process. The results come from 42 samples collected--from various stages of the water treatment process--from Friday, March 21 at 6 p.m. through Saturday, March 22 at 6 a.m.
Results indicate raw water from the Elk River and settled water from post clarifiers (an early stage in the treatment process)--both east and west--are returning non-detectable levels of MCHM. However, results from east and west filters range from non-detectable levels to 0.60 parts per billion (ppb). Results from the finished samples, which have completed all stages of the treatment process, range from non-detectable levels to 0.53 ppb.