Oracle and /etc/limits

Gang,

Here's the scenario:
IBM P660 4CPU, 2GigRAM, AIX 5L, Oracle 8.1.7.1 w/OPS.

Now, here's the problem:
Every now and then a process that belonging to the oracle user will eat up all available memory until it crashes the box.

A spoke to one of the inhouse SysAdmins and he mentioned that the Oracle user is not driven by /etc/limits therefore it can consume all system resources.

Has anyone out there heard anything about having the oracle account not being governed by /etc/limits?

Thanks much!