N.H. Rev. Stat. § 21-P:19

The provisions of this subdivision and any rules adopted under it shall be enforced anywhere in the state by any state trooper, highway patrol and enforcement officer, authorized agent of the commissioner of safety, or by any law enforcement officer within his respective jurisdiction. The officers may detain and inspect any sealed or unsealed vehicle, container, or shipment which contains or which they have reason to believe contains hazardous materials or wastes while in transit or in maintenance facilities or terminals or on other public or private property to ascertain if hazardous materials or wastes are being loaded, unloaded, stored, or transported and to inspect the contents, take samples, and to otherwise insure compliance with the provisions of this subdivision and of all rules adopted under this subdivision. If a seal is opened for inspection, the inspecting officer shall reseal any vehicle, container, or shipment prior to further transportation.