Defining civil rights may not be as easy as one would think.  Rights guaranteed and protected by the Constitution of the United States and various amendments are civil rights.  There are various civil rights laws have made it illegal to discriminate on the basis of race, color, religion, sex, age, handicap, or national origin.  Not all discrimination, however, is illegal and your situation, while looking in from the outside may seem discriminatory because you are white and everyone else is black, may fall in to that category.  Now, it may be that your right is a violation of a union rule and a protected right here without being discriminatory.  The facts on how your company handled the matters in the past  - were black employees entitled to union reps - may come in to play.  I would speak with your union rep here and see what he or she says.  And consult with an attorney if you feel that you are not being supported there as well.  Good luck to you.