The AFL-CIO joined forces with a national environmental group yesterday in a lawsuit that seeks to overturn the Environmental Protection Agency's procedures for regulating pesticides and rescind virtually every pesticide regulation issued by the agency in the last 14 months.

In the lawsuit, filed in U.S. District Court here, the labor federation and the Natural Resources Defense Council accused the agency of setting standards unlawfully in closed-door meetings with the chemical industry.

The suit alleged that "EPA has made decisions that fail to impose adequate restrictions on a host of chemicals suspected of causing cancer, birth defects, genetic mutations and other health hazards . . . ."

The lawsuit refers to "decision conferences," EPA officials and chemical industry representatives review the results of chemical testing, discuss the risks identified and decide what restrictions should be placed on the chemical's use. The conferences were initiated by former EPA administrator Anne M. Burford and her pesticides chief, John A. Todhunter, in March, 1982, as part of the Reagan administration's regulatory reform campaign.

The suit says the practice violates the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Federal Advisory Committee Act and two other laws relating to open decision-making in government.

In addition to seeking an injunction against the conferences, the suit asked the court to set aside any regulatory decisions reached in the meetings and to require the agency to reassess every pesticide rule it has put out since the change was announced, or earlier if the court determines the practice was in use earlier.

The lawsuit said that 60 percent or more of all pesticides in use have not been tested for their cancer-causing potential; 90 percent have not been tested for their ability to cause genetic mutations, and 60 percent have not been fully tested for their ability to cause birth defects.

The pesticide law, FIFRA, now requires tests for each of those risks, but hundreds of pesticides were registered before the law was amended to require the additional tests. In 1972, Congress required the EPA to reevaluate all those pesticides. It is the EPA's method of performing the reviews that is now under challenge.

The suit also challenges the EPA's adoption of revised criteria for assessing the risk of cancer from pesticides.

An EPA spokesman said the agency had no comment on the suit.