Back in 1937 there was a schoolhouse in New London, Tx which was responsible for the odor you associate with natural gas today.
On this day in 1937, a massive explosion caused the steel-framed school
building in New London, in Rusk County, to collapse, killing a reported
298 people. It was the worst school disaster in United States history.
Of the 500 students in the building, only about 130 escaped serious
injury. The explosion, which was heard four miles away, occurred when a
manual-arts teacher turned on a sanding machine and inadvertently
ignited a mixture of gas and air. Three days after the explosion,
inquiries were held to determine the cause of the disaster.
Investigators learned that in January 1937, to save gas expenses of $300
a month, the school board and superintendent had authorized plumbers to
tap a residue gas line of H. L. Hunt's Parade Gasoline Company.
After investigating, the TX Railroad Commission ordered that, because natural gas is almost unidentifiable by people without gas detectors, there be added to all domestic and utility gas an odorizer so anyone would know when the had a gas leak.
This orodizer comes in two types, B.P. Captain and Mercaptan. Both have the sulphery smell that we now associate with gas.