The former chairman of a West German firm alleged to have helped Libya make a suspected chemical weapons plant has been arrested, the Mannheim prosecutor's office said. A spokesman said Juergen Hippenstiel-Imhausen of the Imhausen chemical company was seized in the town of Bochum on suspicion of offenses against export laws. Imhausen-Chemie and several other West German firms are under investigation on suspicion of evading export laws to help Libya build a factory at Rabta. Libya has said the plant will make only medicines, but the United States and other Western governments believe it was designed to make poison gas. Hippenstiel-Imhausen resigned in March, saying he hoped this would help to clear up the affair.