HOSPITAL bosses failed to warn staff or tackle high levels of nitrous oxide on Basildon Hospital’s maternity ward for more than 18 months, the Echo has learned.

NHS workers have accused the trust which runs the hospital of a “cover-up” after the shocking scale of the issue was revealed.

Damning documents from an internal meeting have shown hospital bosses had been aware of high levels of Entonox – nitrous oxide used as pain relief during labour – in the ward since the summer of 2021.

But they only told staff in October this year when units to help clean the air were finally delivered to the hospital.

Acting chief executive Hannah Coffey told the board of directors at a meeting last month: “Urgent action has been taken to reduce levels of nitrous oxide in the air in the maternity delivery suite.

“Approval was given to buy units to help clean the air, but they were only delivered last month.

“And although the issue was logged on the risk register, there had not been proper oversight of the problem, and staff had not been informed.”

She added: “We have apologised unreservedly to the staff who have been working in that area, and have commissioned an independent external investigation to find out what went wrong. We have now taken urgent action to try and address the issue with new standard operating procedures in place to ensure better ventilation and the installation of scavenger units to reduce the amount of nitrous oxide in the air.”

One employee told the Echo: “The suite was dangerous since at least early 2021 and the hospital did nothing about it.

“To think of the poor mothers and babies that have been through the unit.”

They added: “There has clearly been a cover-up in the last 18 months.”

Another said: “The trust was not honest with us about anything.”

Long-term overexposure to nitrous can lead to infertility, according the United States Centers for Disease Control and Prevention.

Trust bosses insist the ward was and is safe for patients, adding it has launched an investigation into the incident.

A spokesman said: “It is perfectly safe for service-users and their families to continue to use the maternity unit as normal.

“We have taken immediate action to resolve the situation and an investigation is underway.

“Support and advice is being offered to our staff while investigations continue.”