20 CFR §802.212

1. (a)Within 30 days after the receipt of a petition for review, each party upon whom it was served may submit to the Board a brief, memorandum, or other statement in response to it.
2. (b)Arguments in response briefs shall be limited to those which respond to arguments raised in petitioner's brief and to those in support of the decision below. Other arguments will not be considered by the Board (see § 802.205(b)).