Any product that comes into contact with water has the potential of contributing both regulated and unregulated contaminants to the water. In order to ensure that these contaminants are not present at levels of toxicological concern, NSF International, along with its Health Effects Task Group, has designed a protocol for the development of maximum allowable level (MAL) values. NSF's system increases toxicological testing requirements as potential human exposure increases. This approach concentrates more resources on a smaller number of high exposures, potentially higher-risk additives, and a reduced level of effort is expended on low exposures, potentially lower-risk additives.