Four former employes of a research laboratory have been charged with giving false safety test results on pesticides and chemicals to the federal government to get the substances on the market, the U.S. attorney's office says.

The tests, conducted by Industrial Bio-Test Laboratories Inc., of suburban Northbrook, were completed during the early 1970s for manufacturers of pesticides, herbicides, arthritis drugs and soap products, the indictment said.

In each case, the laboratory concluded that the chemical under study was safe, the indictment said.

The indictment handed down by a federal grand jury charges the defendants with concealing test results in four long-term studies. They are also accused of lying about the types of tests conducted, the number of animals used and the length of the studies, federal prosecutors said.

Two of the studies were performed for Chemagro, now a division of Mobay Chemical Corp.; one for the herbicide Sencor, which is widely used in the Midwest on soybean and corn crops, and the other on the pesticide Nemacur.

Another report was on TCC, an antibacterial agent used in many deodorant soaps and manufactured by Monsanto Corp. The fourth study was on Naprosyn, a drug used in the treatment of arthritis and manufactured by Sntex Corp. FDA spokeswoman Faye Peterson said new tests on TCC and Naprosyn have shown them to be safe.