Expunge an FBI record? Criminal Records, Expungement

My jurisdiction is: NY

28 years ago, I was young, dumb and angry. The result is that at 17 I was sent to prison for a year; the conviction was 2nd degree attempted arson. The state was NY. I was granted Youthful Offender status. I got religion in prison and never looked back; it was my one and only brush with the law.

Now I'm a teacher, certified in PA. I've been out of the game a few years and want to go back to substitute teaching. My conviction never showed up in the PA background checks, but now they require an FBI background check. There, my conviction, sentence of one to four years, entry into state prison (and which one) and subsequent release on parole are all displayed- with the annotation of Youthful Offender Adjudication.

School Boards and Superintendents are highly political creatures. This conviction is the kiss of death to my career. What, if anything, can I do to have the record expunged?