Can Private Parties Enforce Federal Regulations?

As with most questions in American Administrative Law, the answer is it depends. It depends on what the enabling statute (the statute either creating the agency or the agency's task) says. The law blog JURIST has a good example of a statute that allows private parties to enforce regulations and an instance where a federal judge found that environmental groups had standing to sue to enforce the regulations:

A federal judge on Tuesday permitted two environmental groups to sue a Texas refinery owned by ExxonMobil Corp. [corporate website] for failing to enforce federal environmental standards. The Sierra Club and Environment Texas [advocacy websites] filed the lawsuit [Reuters report] in December in the US District Court for the Southern District of Texas [official website] against ExxonMobil's Baytown, Texas, refinery and the adjacent chemical plant for allegedly releasing over 8 million pounds of pollutants beyond the levels permitted under the CAA in the last five years. The Clean Air Act (CAA) [materials] contains a provision permitting private individuals to seek enforcement of federal pollution laws when the US Environmental Protection Agency (EPA) [official website] fails to do so.

you can read the rest here.