The Richmond County Superior Court lawsuit names Modern Welding Co. of Kentucky, Modern Welding Co. of Georgia and Dresser Industries of Delaware as defendants. The suit was filed on behalf of Jennifer Kohl and daughter, Kelsey; and Tonya Rowland and children John and Lindsey.

Heinrich ``Heins'' Kohl, 25; John Rowland, 35; and George Sanders, 42, died of injuries suffered March 13 at the BP Amoco Polymers plant when an explosion ripped through a dump tank at the south Augusta plant.

``I think you will find our law firms like to move expeditiously to resolve disputes,'' said Reuben A. Guttman of Provost Umphrey Law Firm, who is representing the families along with Jane Brown of the same firm and Richard A. Middle of Suggs, Kelly and Middleton of Savannah.

Mr. Guttman said his firm specializes in litigation involving chemical plant explosions and complex litigation cases in general.

The cause of the blast is still under investigation, but a preliminary finding indicated a tank's pressure gauge falsely read zero before the three employees went to open the chemical dump tank, the Georgia Department of Labor has reported.

The lawsuit filed Friday alleges the Modern Welding Co. of Kentucky and the Modern Welding Co. of Georgia manufactured the polymer-containing vessel that exploded, and that Dresser manufactured the defective pressure gauge.

A lawsuit represents only one side of a dispute. The defendants have 30 days to respond.

The lawsuit alleges the tank and gauge manufacturers knew or should have known that their products were not suited for storage and measurement of pressure of volatile chemicals and a fatal explosion could result. Further, the lawsuit says the manufacturers failed to properly warn either the BP Amoco Polymers plant or workers such as Mr. Kohl and Mr. Rowland of inherent dangers of their products.

The vessel that exploded is used to collect byproducts in the production of a heat-resistant plastic called Amodel. The state labor board reported the three workers had removed bolts from a 5-foot cover plate, believing the pressure reading inside was zero, when the cover blew off.

Since the explosion, the Amodel unit has been under investigation by the U.S. Chemical Safety and Hazard Investigation Board, the federal Occupational Safety and Health Administration, the Georgia Department of Labor and an internal BP Amoco team.

Plant spokeswoman Pam Barbara said Monday the other units - including the sulfone monomer unit, the Xydar unit and the compounding unit - should be up and running by midweek. Since the blast, an outside team of experts has been reviewing employees' safety procedures and processes, she said.

The Amodel unit might be running again by the end of July, Ms. Barbara said. Meanwhile, the plant's customers are being supplied through May on an allocation basis, and after that the company might help them find other sources.

The lawsuit seeks unspecified compensatory and punitive damages under the state's Strict Products Liability law, and for negligence and gross negligence and wrongful death.

Staff Writer Johnny Edwards contributed to this story.

Reach Sandy Hodson at (706) 823-3226 or shodson@augustachronicle.com.