N.H. Rev. Stat. § 109:10
If, while any fire-fighting personnel or equipment pertaining to a New Hampshire municipality is engaged in rendering emergency fire assistance upon call of a municipality in another state, a fire emergency develops within the state of New Hampshire, the governor shall determine whether such fire-fighting personnel and equipment shall be recalled to New Hampshire in order to meet the fire emergency in this state. Under such conditions the decision of the governor shall supersede any agreement or other arrangement for mutual assistance entered into as provided in RSA 109:12. Upon the issuance by the governor of such order of recall, through the state director of civil defense, the fire-fighting personnel and equipment shall forthwith return to the state of New Hampshire.
RSA 109:10
1949, 257:1, par. 10, eff. June 16, 1949.