It is possible. The law prevents you from being terminated because of a bankruptcy BUT it does not prevent the security clearance from being revoked. And if your job is requires the revoked clearance, then your position can be terminated then.
Security clearances are not automatically revoked because of a bankruptcy, either, but it certainly doesn't help. If you're going BK because of a bad real estate deal, or a specific event, likely your clearance will stay in effect. If you're going BK because of gambling, alcohol-related problems, or other "moral problems", you're probably in trouble.