The Manfredonia accidental release of arsenic took place near the Italian town Manfredonia

Manfredonia

Manfredonia is a town and comune of Puglia, Italy, in the province of Foggia, from which it is 35 kilometres northeast by rail. Manfredonia is situated on the coast, facing east, to the south of Monte Gargano, and giving its name to the gulf to the east of it...

 in September 1976 at the Enichem petrochemical plant, which produced fertilizers and caprolactam

Caprolactam

Caprolactam is an organic compound with the formula 5CNH. This colourless solid is a lactam or a cyclic amide of caproic acid. Approximately 2 billion kilograms are produced annually...

, a precursor in the manufacture of nylon

Nylon

Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...

. A scrubbing tower for the synthesis of ammonia

Ammonia

Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

gases blew up, releasing into the atmosphere several tons of potassium carbonate

Potassium carbonate

Potassium carbonate is a white salt, soluble in water , which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid...

 and bicarbonate solution containing arsenic trioxide

Arsenic trioxide

Arsenic trioxide is the inorganic compound with the formula As2O3. This commercially important oxide of arsenic is the main precursor to other arsenic compounds, including organoarsenic compounds. Approximately 50,000 tonnes are produced annually...

. One hundred and fifty people were admitted to the local hospital for arsenic poisoning.