London Fire Brigade officials have been interviewed under caution by police investigating the Grenfell Tower disaster.
Scotland Yard detectives questioned the body over its duty to protect the public and its own employees from health and safety risks.
London fire commissioner Dany Cotton said: “We have always been subject to the Metropolitan Police investigation and I want to ensure it is accurately and publicly known the brigade has now, voluntarily, given an interview under caution in relation to the Health and Safety at Work Act.
“As the fire and rescue service attending the Grenfell Tower fire it is entirely correct that we are part of the investigation. Hundreds of firefighters, officers and control officers have already provided voluntary police interviews and we will continue to do all we can to assist investigators.
“The bereaved, survivors and residents need answers and we must all understand what happened and why to prevent communities and emergency services from ever being placed in such impossible conditions ever again.”
The fire brigade was heavily criticised for aspects of its response to the blaze, which killed 72 people on 14 June 2017.
Firefighters who were initially called to a small kitchen fire were unable to stop the flames spreading rapidly up cladding on the outside of the flat block, and some residents were trapped in their flats.
Witnesses described seeing people waving from windows or shining lights in attempts to attract help when they were not rescued by firefighters, and the standard “stay put” advice for people to stay in their flats was not officially abandoned until two hours after the fire started.
The London Fire Brigade said the Grenfell disaster was the largest residential blaze in its history and it was still supporting firefighters, control officers and other staff who were involved.
“The Brigade understands the important legalities and sensitivities of the investigation but is making this information public in accordance with its commitments to transparency and to assisting in every way possible to prevent such a devastating fire from ever happening again,” Ms Cotton said.
It was interviewed as a corporate body, rather than an individual, in relation to sections two and three of the Health and Safety at Work Act.
They include a duty to ensure, so far as is reasonably practicable, the health and safety and welfare of all employees and make sure others are not exposed to health or safety risks by its conduct.
It is one of 17 interviews under caution so far carried out by police investigating the Grenfell Tower fire.
“The number will continue to increase as progress is made with the investigation,” a spokesperson for the Metropolitan Police said.
“As previously stated, the interviews under caution are for gross negligence manslaughter, corporate manslaughter and health and safety offences.”