43 C.F.R. § 28.3
In the absence of a reciprocal fire protection agreement, each agency head may provide emergency fire protection will not jeopardize the property of the United States by making it impossible for the agency head to protect the property of the United States and such assistance is determined to be in the best interest of the United States. The providing of emergency assistance shall not be in the best interest of the United States and may not be granted by an agency head if: