Three additional private wells near Hercules' Bacchus Works have turned out to be clean of solvent contamination, the aerospace company announced Monday.

Independent laboratory tests discovered no evidence of industrial solvents in the wells, located north of the plant. They were studied after Hercules announced a test well at the northern border of the plant turned up traces of dangerous solvent that violated federal drinking water standards.The contamination within Hercules' boundary was announced March 10. Hercules officials said they were trying to find the locations of all private wells being used in an area bordered by 35th South and 41st South and by 64th West and 80th West.

Results from the first private well to be tested showed no trace of solvents and follow-up testing for three more private wells also detected no trace of solvents, according to company officials.

Ruth L. Novak, the Bacchus Works' vice president and general manager, said a fifth private well will be tested when the pump is turned on for irrigation next month. It is the last nearby well and is used for drinking, irrigation or watering animals.

"The analysis is capable of detecting compounds in the water as low as one part per billion," said Hercules spokesman Ted Olsen. That is considerable considerably cleaner than required by federal drinking water standards.