CHARLESTON, W.Va. -- Continued reports from residents about licorice-smelling water long after the region's water system was flushed are a clear indication that chemicals from the January leak into the Elk River haven't been completed cleaned out, experts said Tuesday.While state officials and the water company tout "non-detect" test results, such results help to confirm that Crude MCHM can be smelled at lower concentrations than laboratories can measure, the experts said."By now, things should have been flushed out," said Michael McGuire, an environmental engineer working with the West Virginia Testing Assessment Project, or WVTAP. "It clearly hasn't been; because people are still smelling it."McGuire and other experts working with WVTAP answered questions Tuesday about two reports issued a day earlier. The reports, funded by the Tomblin administration, examined the "odor threshold" for MCHM and provided a summary of published research about the toxicity of chemicals involved in the Jan. 9 Freedom Industries leak.The most significant new information in the reports was a finding that humans can detect -- but not clearly identify -- the smell of Crude MCHM at concentrations as low as 0.15 parts per billion. State officials previously had thought the odor threshold was about 1.0 part per billion.Under the WVTAP's new odor threshold, humans could smell MCHM at levels far below the controversial 1.0 part-per-million health "screening level" put together by the U.S. Centers for Disease Control and Prevention. One part per million equals 1,000 parts per billion.However, a team of WVTAP experts has yet to meet to begin a separate review of how the CDC developed that health-screening number, and the CDC's work has been strongly criticized by independent public-health experts.Craig Adams, a Utah State University environmental engineer working with WVTAP, said his literature review published Monday revealed far less data about MCHM's potential health effects than would normally be needed to set an official drinking-water standard for the chemical."There is certainly much, much less [data] than for a compound for which they're making a regulatory determination," Adams said during a conference call Tuesday with members of the news media and some environmental-activist groups.Adams and McGuire conducted their work as part of the WVTAP project, launched last month by Gov. Earl Ray Tomblin amid significant public pressure over concerns about lingering and long-term impacts of the leak that contaminated the drinking-water supply for 300,000 residents in a nine-county region. Jeff Rosen, president of a the Corona Environmental consulting firm, and Andrew Whelton, an environmental engineer with the University of South Alabama, are hiring experts from around the country to assist with WVTAP's work.Next week, the project plans to make public the results of water sampling that Whelton conducted at 10 homes across the region.Previously, state government officials had tested water only at West Virginia American's Elk River plant, and at public locations such as fire hydrants and schools. Whelton's research aims to figure out if something about different sorts of plumbing systems has caused MCHM or other spill chemicals to be absorbed into those plumbing systems, and periodically re-released into residents' drinking water.Locally, some officials have downplayed the lingering-odor complaints, arguing that the levels humans can smell are far below what the CDC's calculation said would be likely to make people sick.However, McGuire has argued in some of his published work that water utilities and regulators need to take complaints about odor and taste of water more seriously, regardless of whether direct health impacts are involved or not."Taste and odor problems in water supplies that are not solved and that recur over time could engender an outrage reaction and drive the public to clamor for immediate solutions to situations which they perceive as risky," McGuire wrote in one 1995 paper, published in the journal Water Science and Technology.McGuire explained Tuesday that humans instinctively think that drinking water that smells bad, or even unusual, isn't good for them to drink."What do we do when we take a quarter of milk out of the fridge that's been in there a while? We take a smell of it," McGuire said. "We've learned by habit that our sense of smell can warn us of things that are bad for us."With chemicals in drinking water, McGuire said, that instinct is sometimes correct - but sometimes not."There is not a direct relationship between odor and toxicity," McGuire said. "For some compounds, you can smell it before it is bad for you, and with others it is the reverse."Still, McGuire said, the goal must be to not have any of an industrial chemical like MCHM in drinking water, and certainly to not have drinking water that smells like black licorice. Given the very low odor threshold for MCHM, it's not yet clear exactly how that goal will be achieved."In a normal situation, you would have expected by now that it was flushed out," McGuire said.Knowing a more accurate number for the chemical's odor threshold will help officials know more about at what the public might no longer notice MCHM. And additional WVTAP research by Whelton could help provide answers about how the chemical has stayed in the system or homes, and help officials begin to figure out how to get it out."There is a tremendous amount of information that needs to be obtained," Whelton told reporters Tuesday. "These questions need to be answered."Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.