Yara North America has agreed an exclusive supply contract with LSB Industries for its Earthpure DEF. Yara will distribute and market the LSB's DEF under its own Air1 brand, a brand that Yara has used successfully in the European AdBlue market, and is in the process of rolling out across the US in collaboration with Mansfield Oil. LSB has announced  that it will produce the DEF at its Cherokee Nitrogen site in Alabama - the company's only urea production facility.