2,4-Dinitrophenol (2,4-DNP, DNP) is an organic compound with the formula HOC6H3(NO2)2. It is a yellow, crystalline solid that has a sweet, musty odor. It sublimes, is volatile with steam, and is soluble in most organic solvents as well as aqueous alkaline solutions. It is a precursor to other chemicals and is biochemically active, inhibiting energy (ATP) production in cells with mitochondria. DNP is considered an important environmental contaminant by the United States Environmental Protection Agency.
From various news sites:
The tablets that Parry is believed to have taken shortly before her death are being tested for a toxic substance called dinitrophenol or DNP, police said. Generally described as a yellow, powdery substance in medical literature, dinitrophenol has been used as a black market weight-loss drug for decades, authorities said.
The substance is illegal for use in a diet drug or supplement in the United States, according to a spokeswoman for the U.S. Food and Drug Administration.
Parry's mother, Fiona Parry, recounted the details leading up to her daughter's death on a post on the police department's website.
Fiona Parry said her daughter became ill after taking the diet pills but didn't initially realize the gravity of her situation. Even after taking herself to a local hospital, her daughter said she did not initially feel gravely ill, Fiona Parry recalled.