Under the Clean Water Act, EPA may weigh the costs of regulations against the benefits achieved to protect fish and other aquatic organisms, the U.S. Supreme Court ruled last week. The high court’s 6–3 decision involved regulation of cooling-water-intake structures at existing power plants and industrial facilities. The decision, authored by Justice Antonin Scalia, pointed out that these structures threaten aquatic life by squashing fish against intake screens and sucking up organisms into cooling-tower pipes. At issue was a 2004 Bush Administration EPA rule requiring facilities to limit the number of organisms killed by cooling-water intakes. Conservation groups challenged the rule, saying it did not minimize the number of fish killed at the facilities. In 2007, a federal appeals court found unlawful a part of the rule allowing some plants, on the basis of a site-specific cost-benefit analysis, to adopt less stringent measures to protect aquatic life. The Supreme Court said the Clean Water Act allows EPA to use cost-benefit analysis when establishing a national regulation for cooling-water intakes and for site-specific variances to the rule.