Here are a few things to consider in your quest for solving this difficult question.
And how I would go about explaining it to management.
1. Put a dollar value on system outage, So 1 hour equals $100.00 or whatever might apply to your company. You may even want to get management involved in this.
2. Have the EMS dept request exactly what it is they need root access for, details are important. So you will know what commands are need to run and why.
3. Lay out a plan to solve those dept issues that do not involve giving root access. Like using sudo, or a formal request to have certain commands run for them at a certain time, etc.
4. Show Management that the wonders of a UNIX system are many ways to solve any given problem, not just giving root access to all that request it.
5. List some reasons that root access is a risk to the company. Some examples.
A) Simple mistakes can cost hours of downtime to fix.
B) No way to easily track who did what, therefore adding to the time to fix mistakes.
C) Data Integrity, For instance can the financial dept risk a mistake that may not be found for weeks or days, or worst yet at month end.
D) Confusion over who is responsible for what, causing greater lead time in solving other problems that may seem related to storage.
These are just a few idea's I hope you can use. A well thought out plan works best when approaching management with what's in the best interest of the company.