; and (ii) add a type of exposure-related cancer to the definition by rule, upon a showing by a petitioner or on the Director’s own determination, in accordance with this paragraph. (B) Basis for determination The Director shall add a type of exposure-related cancer to the definition of exposure-related cancer under paragraph (1) upon a showing by a petitioner or the Director’s own determination, based on the weight of the best available scientific evidence, that there is a significant risk to public safety officers engaged in public safety activities of developing the type of exposure-related cancer. (C) Available expertise In determining significant risk for the purpose of subparagraph (B), the Director may accept as authoritative and may rely upon recommendations, risk assessments, and scientific studies by the National Institute for Occupational Safety and Health, the National Toxicology Program, the National Academies of Sciences, Engineering, and Medicine, and the International Agency for Research on Cancer. (D) Petitions to add to the list of exposure-related cancers (i) In general Any person may petition the Director to add a type of exposure-related cancer to the definition of exposure-related cancer under paragraph (1). (ii) Content of petition A petition under clause (i) shall provide information to show that there is sufficient evidence, based on the weight of the best available scientific evidence, of significant risk to public safety officers engaged in public safety activities of developing such exposure-related cancer from their employment. (iii) Timely and substantive decisions Not later than 180 days after receipt of a petition under this subparagraph, the Director shall grant or deny the petition by publishing in the Federal Register a written explanation of the reasons for the Director’s decision. The Director may not deny a petition solely on the basis of competing priorities, inadequate resources, or insufficient time for review. (iv) Notification to congress Not later than 30 days after