; (ii) requires a response by at least 1 eligible entity described in paragraph (6) for which the Secretary estimates the costs to the eligible entity to be at least $15,000; and (iii) results in a serious injury, fatality, or substantial property damage. (B) Substantial property damage The term substantial property damage means damage to public or private property or the environment (including clean up costs) the Secretary reasonably estimates to be more than $45,000. (2) Establishment of program Not later than 1 year after the date of enactment of the Railway Safety Act of 2023 , the Secretary, in consultation with the Administrator of the Federal Emergency Management Agency and the Administrator of the Environmental Protection Agency, after providing an opportunity for notice and comment, shall establish an emergency response assistance program to provide immediate financial assistance to communities responding to a significant hazardous materials transportation incident. (3) Significant hazardous materials transportation incident (A) In general The Secretary shall have the authority to declare a significant hazardous materials transportation incident. (B) Guidelines The Secretary shall establish and publish guidelines to determine whether a significant hazardous materials transportation incident has occurred. (4) Release of funds (A) In general The Secretary shall immediately make available from the amount set aside under subsection (h)(3) in the Hazardous Materials Emergency Preparedness Fund established under subsection (h)(1) (referred to in this subsection as the Fund ) up to $10,000,000 to quickly reimburse eligible entities described in paragraph (6) that responded to a significant hazardous materials transportation incident if— (i) the Secretary declares the incident a significant hazardous materials transportation incident