When Alma made the highest-octane gas in the world

In 1953, the highest-octane gasoline on the planet was made in Alma. Octane is the number on the pump that tells you how hard a fuel can be squeezed before it knocks, and Leonard Refineries hit 96 — a first for any refinery anywhere. Not bad for a company that started seventeen years earlier with a plant that could barely do the job.

When J. Walter Leonard bought the half-built Alma refinery in 1936, it was a runt. It could process only 2,500 barrels of crude a day and turn out gasoline rated 40 to 50 octane, which is to say weak. Leonard started improving it almost immediately, and in 1938 he bought the old McClanahan refinery over in St. Louis and hauled most of its equipment to Alma. The crude came up from Michigan’s own oil fields at first, then by pipeline from the south, and by 1956 from Canada.

The refinery sprawled along both banks of the Pine River on the east side of town, and for decades it was one of the reasons Alma had paychecks. Leonard’s tanker trucks and its gas stations were a familiar sight across the state.

Then the story shrank back down. In 1970 Leonard merged with Total Petroleum and took the Total name; in 1972 the new owners moved headquarters to Denver and the local roots went with them. The plant kept running under later owners until it shut in 1999, and the buildings came down in 2003. What it left behind in the river became a long cleanup of its own. But for a stretch of the twentieth century, the fuel that beat the knock anywhere came out of a Gratiot County town most drivers never had to think about.