Final answer:
The amount of gasoline that requires a safety can with a self-closing lid is subject to local job site regulations and can't be precisely specified without further details. Safety cans are necessary due to the flammability of gasoline and the need to control its vapors and prevent accidents.
Step-by-step explanation:
When considering the storage of gasoline on a job site, it is important to adhere to safety regulations which may require the use of a safety can with a self-closing lid. These regulations are in place due to the combustible properties of gasoline. However, without a specific regulatory standard provided, we can't give an exact threshold for when a safety can is required. This kind of information would ordinarily be set by workplace safety authorities or regulations such as those from the Occupational Safety and Health Administration (OSHA) in the United States. For precise requirements, you would need to consult the local regulations in your area.
Understanding the properties of gasoline is important in comprehending why these safety measures are necessary. Gasoline has a density of 0.75 kg/L, and when gasoline burns, it significantly contributes to CO2 emissions. For example, burning a tank of about 50 L (13 gallons) of gasoline, which has a mass of about 38 kg, will produce around 110 kg of CO2. Additionally, gasoline should be stored at temperatures below 120 °F (48.8 °C) to prevent increased pressure buildup and potential combustion, highlighting the importance of proper storage to ensure safety.