An attorney for a former employee at the Koch refinery in Rosemount portrayed him as a good worker who was fired because he reported serious environmental violations by the company. Charles Chadwell is suing Koch Petroleum Group under a state law that protects whistleblowers from retailiation.The case went before a 10 person civil jury yesterday in Minneapolis. An attorney for Koch told the jury Chadwell was fired for "legitimate and lawful reasons." Minnesota Public Radio's Mary Losure reports. Charles Chadwell is a former waste water treatment operator at the Koch refinery in Rosemount. He was fired in 1997, eight months after he reported environmental violations to the Minnesota