The study found no relationship to fetal deaths, but the likelihood of neural tube defects was tripled by exposure to THMs at levels exceeding 80 parts per billion. Neural tube defects are known to be associated with vitamin B12 deficiency and the letter pointed to studies showing that vitamin B12 use by the body can be disrupted by chloroform, one of the four main trihalomethanes in chlorinated drinking water. Indicators of water quality were taken from public water supply companies. No data were available on the amount of water ingested. Bubbling ozone through water kills bacteria effectively, avoids the distinctive taste and odor of chlorine in the treated water, and produces no dangerous trihalomethanes.
Many people buy bottled water simply to avoid the taste of chlorine.
U.S. EPA is currently setting new standards for trihalomethanes in drinking water. Still, since several studies link trihalomethanes at 75 ppb or even less to increased miscarriages, EPA's new standard seems dubious even before it has been established. American water suppliers seem stuck on chlorination as the best way to disinfect drinking water. However, many European cities, and some Canadian cities, such as Ottawa, have long ago turned away from chlorination in favor of ozonation to disinfect their water. The Santa Clara Valley Water District in California has announced that it is switching to ozonation over the next 5 to 8 years, as has the city of Las Vegas, Nevada.