Editing error messages or disabling specific system errors

I have the need to block or change the look of certain (not all) error messages that are native to IQAN. 

My specific need has to do with color. I am not allowed to display any RED on the screen due to safety reasons of the field that this is going to be used in. If i could somehow edit the messages and change from the RED icon that displays that would be fine. 

If anyone has incite on this, i would appreciate it. 

 I know that i have the ability to block all messages or select which modules messages that i want to allow but i would like to keep these messages and simply change how they appear on the screen.