A Cedar Creek sewage treatment operator is facing charges of stealing concentrated chlorine from the Seaford plant to run his pool-cleaning business.

William Supple, 44, of Massapequa, also is facing a drug possession charge after police said they found a large bag of amphetamines in his locker after the county fired him on Tuesday.

Supple was caught stealing 30 gallons of sodium hypochlorite -- a concentrated chlorine bleach solution typically used to clean swimming pools -- from a plant storage tank and putting the containers in his car, said Chris Munzing, a spokesman for the Nassau district attorney's office.

"It appears he had his own personal economic development program," said County Attorney John Ciampoli, who doubles as Nassau's commissioner of investigations.

The investigation, Ciampoli said, has been going on for several months. .

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Supple is charged with one count each of official misconduct and petty larceny.

Thursday night, in a phone interview, he denied the charges.

When plant employees opened Supple's locker, police said, they discovered the pills. He was charged with seventh-degree criminal possession of a controlled substance.

He was freed without bail and is due back in court on the drug charge on Sept. 12 and the theft charges on Sept. 28. He faces up to two years in prison.

Supple has worked for the county since 1985. In 2010, he earned more than $120,000, including overtime, records show.