Domestos thick bleach is safe, both for people and the environment, when used properly. In use, it is broken down rapidly, almost entirely into common salt and oxygen (or water). The active component of bleach, sodium hypochlorite, has been in use for over 200 years and is the most commonly used household disinfectant. Despite its long-term and widespread use, no significant environmental problems associated with its use have been identified. As with all products, to get the best and most efficient results from bleach, follow the dosing instructions on the pack.