Appeals under the Occupational Safety, Health and Working Conditions Code require filing within thirty days, with discretionary extension for sufficient cause. Appeals against orders under section 3 lie to an appellate officer notified by the appropriate Government and must be filed within thirty days of communication; the appellate officer may admit late appeals for sufficient cause. On receipt, the appellate officer must give the appellant an opportunity to be heard and dispose of the appeal within thirty days from receipt, creating an expedited review process with a time-limited filing rule and a discretionary extension for delay.