EPA will reconsider parts of a controversial air pollution regulation, the agency announced last week. The rule, issued last year, rolls back requirements for installation of modern air pollution control equipment when upgrades to facilities increase emissions. This new source review rule is broadly supported by industry, including chemical manufacturers. A federal court has put the regulation on hold while it considers a legal challenge to the rule by environmental groups, 14 states, and dozens of cities. EPA says it will reexamine a section of the regulation allowing businesses to modify plants without adding pollution controls if the cost of new equipment does not exceed 20% of the replacement value of the entire manufacturing unit. In addition, the agency will reevaluate the legal basis for the rule. Industry groups say they expect the rule to remain intact after EPA's reexamination, which will be completed later this year. Environmental organizations characterize the agency's move as an attempt to strengthen a weak legal backing for the rule.