With grease being used to make biodiesel, and its price tripling in the past two years, thieves are breaking into the outdoor bins at restaurants to steal it, CSMonitor reports. Yellow grease, the byproduct of boiling and filtering raw grease and what gets turned into biodiesel, trades on US commodities markets for 32 cents per pound.

The problem, according to Christopher Griffin, director of legal affairs for Griffin Industries, a company that collects raw grease in 20 states and turns it into yellow grease, is that there’s no free grease anymore – it’s all under contract. So people new to the business who can’t get the volume of grease they want, “just steal it,” Griffin says.

And it’s not just commercial operators battling it out for the grease. Individuals are also stealing grease to make biodiesel at home.

Last year, San Francisco launched SFGreasecycle, a free program in which the city will pick up used cooking oil and grease from local restaurants, turning them into biodiesel to run city vehicles.