When it was allowed to expand again, it reached the flash point immediately, creating enormous amounts of heavy gas.
The low-pressure air cylinders were lubricated with "High Test" oil, having a flash point of 600° Fahr.
The flash point of an oil is that temperature at which it will form an inflammable vapor.
The flash point of kerosene may be between 70 and 150 degrees Fahrenheit, depending upon the grade.
For illuminating purposes, do not use kerosene with the flash point lower than 120 degrees Fahrenheit.