A coroner fears there could be more ice hockey deaths if neck guards are not worn following a fatal injury suffered by American player Adam Johnson.
The Nottingham Panthers player, 29, was cut by a skate during a match against the Sheffield Steelers on October 28.
Last week the UK's Elite Ice Hockey League said it would not make neck guards mandatory but would "strongly encourage" players and officials to wear them.
The English Ice Hockey Association (EIHA), in a change to regulations, has said the guards will become mandatory from 2024, but the Elite League, which includes the Panthers, is not under the governing body's control.
Sheffield's senior coroner Tanyka Rawden, who opened the inquest into the death of Johnson on Friday, has written a prevention of future deaths report.
The report, which is addressed to governing bodies Ice Hockey UK and the EIHA, says: "In my opinion there is a risk that future deaths will occur unless action is taken. In the circumstances it is my statutory duty to report to you."
"In due course the inquest will consider whether the use of a neck guard or protector could have prevented Mr Johnson's death," it adds.
"At this stage in my investigation however, I am sufficiently concerned that deaths may occur in the future if neck guards or protectors are not worn."