A former Waterbury Parks Department worker has been charged with poisoning his boss’s oatmeal after an argument over the employee’s job performance. William Lampron is accused of lacing the oatmeal with SpeedyDry, a chemical substance that resembles cat litter and can be used for soaking up spills on roadways. The Republican-American of Waterbury reported that Lampron’s 50-year-old supervisor ate the oatmeal last month and developed severe stomach problems, but recovered. Lampron, 43, of Naugatuck, was charged Wednesday with felony assault and reckless endangerment. He posted $5,000 bail and is due in Waterbury Superior next Wednesday.