A third horse fatality on the set of the drama “Luck”, starring Dustin Hoffman and Nick Nolte, has prompted the cancellation of the HBO series. After the final two episodes of the first season air, the show will not return, though season two was already in production.

Earlier this week, at Santa Anita Park racetrack, a horse who was being led to stable by a groom sustained a head injury and had to be euthanized after it reared, slipped and fell backwards.

Two horses were injured during race scenes for the first season of the show and had to be euthanized in 2010 and 2011.

“While we maintained the highest safety standards possible, accidents unfortunately happen and it is impossible to guarantee they won’t in the future,” HBO said in a statement.

The American Humane Association supports the decision and has agreed to work with HBO to find suitable retirement homes for the show’s horses.

Despite the cancellation, The California Horse Racing Board has promised to “conduct a thorough investigation, which will include a postmortem examination and toxicology testing.”