Greetings and welcome to justanswer,
The chemical pneumonia is the irritation of lung and subsequent inflammation caused by inhalation of gas, fumes, chemical or aspiration of vomit.
The symptoms also depends on the amount and length of exposure.The inhalation of gasoline fumes may cause such symptoms in some cases.The symptoms may appear after a few hrs to days and depends on the severity.
The treatment is symptomatic.
Here is the link for more information
symptoms of chemical pneumonia
Let me know if you have any doubt.