Look up the physical properties of 4-methylcyclohexene below from the most Dangerous Properties of Industrial Materials Sax & Lewis. Use the current edition or you can use the Internet.
Search the UCF Libraries catalog for "dangerous properties of industrial materials"
The call number is T 55.3 .H3 S3
The most recent edition is located in the Reference Collection on the 2nd floor.
However, although Sax's Dangerous Properties of Industrial Materials does include information about OSHA PEL and DOT classification within the entries when available, the entry for "4-methylcyclohexene" does not have that information.
Instead, consider using one of the sources for MSDS or the Chemical Database (University of Akron).
NOTE: Students have reported difficulty locating the OSHA PEL and DOT classification in the above resources as well. "This information is not available from OSHA, Sigma-Aldritch (a vendor supplying the compound) on their MSDS, and as far as I can tell, has never been established by OSHA." Consult with your instructor for additional guidance -- and please post a comment in this box letting us know if you're able to locate a reliable source for the information.
Subsequent suggestions from students: