Most of the C9 fraction is not isolated. Refineries isolate less than one-half percent of the C9 fraction. Oil refineries generally do not isolate 1,2,4-trimethylbenzene from crude oil or from the C9 fraction. The largest users of isolated 1,2,4-trimethylbenzene are chemical companies that make trimellitic anhydride. Companies also use it to make dyes and drugs.
Exposure can also occur when people use gasoline or certain paints and cleaners.
1,2,4-Trimethylbenzene enters the body when breathed in with contaminated air or when consumed with contaminated food or water. It can also be absorbed through skin contact. It may remain in the body, stored in fat, before its removal in expired air or in urine. 1,2,4-Trimethylbenzene evaporates when exposed to air. It dissolves only slightly when mixed with water.