Under the guise of requiring public notice of impending dangers, a lot of local governments around the country are enactingpesticide regulations that are a severe intrusion on business as usual.

The governments will, for instance, require commercial pesticide services to pay an annual registration fee of thousands of dollars or maintain a list of residents allergic to pesticides and demand that each one be notified at least 24 hours before any outdoor application.

The courts are split over whether the cities can enforce such ordinances. The most recent ruling, from the U.S. Court of Appeals in Cincinnati, threw out the regulation.

The regulation conflicted with the Federal Insecticide, Fungicide and Rodenticide Act, the judges said.

A similar ordinance in Montgomery County was thrown out for the same reason in 1986, but the top state courts in California and Maine have held that the federal statute does not preempt additional regulations by cities and counties.

Congress clearly wanted to retain some role for local governments in pesticide regulation.

The federal law specifically says that states can impose their own curbs as long as they are not less stringent than Washington's prohibitions.

The statute also gives some specific authority to a state's political subdivisions, but far less than is given the states.

The mere fact that Congress hasn't given local governments a lot of leeway to enact their own curbs on pesticides is not the end of the matter because the federal law also does not specifically preempt such regulation.

The cities that want to get tough about pesticide use insist that they should be able to go ahead with their programs because they in no way get in the way of the main point of the federal undertaking, which is to reduce the use of potentially dangerous compounds.

The Cincinnati judges, however, found that the federal law had other goals as well, including the establishment of a uniform national policy on pesticide use.

Because a confusing network of different rules in every city and county would undercut this aim, they said, the local regulations must be deemed to be preempted.

In other cases, courts ruled that:

Courts should presume that the Internal Revenue Service is correct. The ruling from the U.S. Court of Appeals in Chicago does not mean that a taxpayer cannot win a fight with the IRS, but it does mean that the taxpayer must have evidence that the government was wrong.

Without such evidence, judges are right to go along with an IRS assessment, the ruling says. (Gold Emporium v. Commissioner, Aug. 14)

Daniel B. Moskowitz is a Washington editor for Business Week newsletters.