Originally released in the civilian market March 14, 1992, the Hummer H1 became known from the photographs published during Operation Desert Storm and the enthusiastic campaign from actor-politician Arnold Schwarzenegger. AM General announced that 2006 would be the last model year for the Hummer H1, with production winding down in June 2006 due to a new emission law for diesel engine vehicles, which took effect in 2007. The final model year of 2006 had the most powerful engine and improved fuel efficiency – about 10 mpg_‑US (24 L/100 km; 12 mpg_‑imp).