check this out!

Locum (the process for emptying the Trash) is using 100% cpu, which is in turn heating up your computer.

Locum sometimes uses up extreme amounts of cpu when emptying the trash, usually when there are lots of files to destroy.

Locum should go back to 0% when the trash is empty.

 

You said you were doing a secure erase. This involves writing to the hard disk (in this case a bunch of zeroes). Writing data will draw on the CPU.

Unless you share your laptop with some good CompSci students or some very computer friendly folks and are worried about privacy, you don't need to secure erase your trash. All you're doing is shortening the life of your drive.