An Iowa man who filed a lawsuit claiming he incurred lung damage after being exposed to diacetyl, the controversial chemical used in buttery flavoring for microwave popcorn, has reached a settlement with the company that made the flavoring.

John Weimer Jr. filed the lawsuit against International Flavors & Fragrances Inc. for being negligent. Weimer stated that the company knew the flavoring posed a health hazard, but did not fulfill its duty to inform the public and governmental agencies.

Diacetyl is linked to a respiratory disease known as popcorn lung. While posing no risk to popcorn consumers, the vapors from the chemical flavoring cause lung damage in popcorn plant workers. Weimer says he was injured while working as a manager at the Snappy Popcorn Company plant in Breda, Iowa.

The amount of the settlement cannot be released due to provisions prohibiting both sides from discussing the terms. Other workers from the plant have filed similar lawsuits for undisclosed amounts, and the Snappy Popcorn plant discontinued its use of the product.