Jay Brenton Liptrot, 43, was among the first on the scene of the blaze in Prestatyn in October, 2012.
He gave evidence at the trial of one of the tenants, Melanie Smith, who was convicted of five murders.
Mr Liptrot will appear before Prestatyn magistrates on Friday.
The blaze resulted in the deaths of Lee-Ann Shiers, 20, her partner Liam Timbrell, 23, their son Charlie, 15 months, Ms Shiers' nephew Bailey, four, and niece Skye, two.
A firefighter who owned the house in which five people died in an arson attack has been summonsed to appear in court in connection with manslaughter through gross negligence.