A 60-year-old man has been charged with risking a catastrophe after he allegedly stole more than 200 grams of potassium cyanide in December from the Montgomery County laboratory where he worked — claiming he wanted it for pest control at his home — and then dumped it into a Bucks County storm drain inlet after he found out he was under investigation, authorities said Tuesday.

Richard O'Rourke, of the 2800 block of Highland Road in Warrington, was at his job as a senior analytical chemist at Merck & Co. in Upper Gwynedd when he was witnessed by a coworker taking 219.79 grams of potassium cyanide — the equivalent of a cup — without authorization Dec. 14, authorities said. Potassium cyanide is the crystal form of the fast-acting chemical that prevents cells from using oxygen, causing them to die, according to the Centers for Disease Control and Prevention.

The next day, after being notified by the coworker that the incident had been reported to the company, O'Rourke allegedly dumped the potassium cyanide into a stormwater inlet in the area of County Line Road and Street Road, between Easton Road and Second Street Pike. O'Rourke had told the coworker that he wanted the poison for a "coon" problem at home, authorities said.

The FBI and the Pennsylvania Department of Environmental Protection joined the investigation, and the DEP began monitoring the water supply in the area. The Philadelphia Water Department and Aqua PA also began testing and monitoring samples from intake facilities they operate in the vicinity.

The DEP and the water companies remained on high alert for two weeks, authorities said. After intensive testing and monitoring, they found no toxic impact, authorities said. A significant rainfall a few days after the chemical dumping should have diluted and washed out the poison, the DEP said.

O'Rourke, who cooperated with investigators, was arrested Monday and charged with causing or risking a catastrophe, theft, and related offenses. He posted $35,000 bail and was released. His preliminary hearing before Magisterial District Judge Suzan Leonard was scheduled for March 6.