NHS maternity staff say gas exposure left them 'panicked'

More than 120 NHS midwives and maternity workers will share £735,000 in compensation after being exposed to dangerously high levels of a medical gas given to women as pain relief in labour.

Staff at Basildon University Hospital in Essex were found to have breathed in nitrous oxide, also known as Entonox or gas and air, during long shifts for months and years.

The Royal College of Midwives (RCM) says it is the largest group legal action brought by midwives in the UK after members were exposed between 2021 and 2023 due to poor ventilation on the maternity unit.

The Mid and South Essex NHS Foundation Trust, which runs the hospital, says it has apologised to staff and "should have acted faster".

"Everyone was panicked, everyone was angry, everyone felt really let down," says one health worker who was among those to bring the successful compensation claim.

"When it all came out, all the management came out... and [said] they're here to support us.

"Actually, they didn't do that for over a year - they knew about these levels."

The employee, who the BBC has agreed to keep anonymous, says it is "hard to stomach" that she and her colleagues had been unaware they were being exposed to high levels of the gas.

According to an internal report from Basildon University Hospital, some members of staff were exposed to levels up to 30 times higher than the legal workplace exposure limit between 2021 and 2023.

The affected staff were also not told for 16 months about test results commissioned by the trust, which showed their exposure had breached safety thresholds.

"As healthcare practitioners, if something goes wrong with a patient, we have a duty of candour," she says.

"We have to tell them and their families what has happened, and be open and honest... and our management didn't do that with us - their own staff."

She says although staff were always busy in the department, they were complaining of being "overly tired", as well as suffering from brain fog and low B12 levels.

The health worker says some colleagues have left following the ordeal, which has made her feel like a number rather than a respected professional.

She adds she is "scared" for her long-term health, adding: "We've managed to get a payout, but we've been working in that for over a year," she says.

"In 10 years' time, is our health going to be OK? You lose all trust that your employers want anything good for you."

Daniel Poet, from Thompsons Solicitors, represented the majority of claimants and says while the trust knew about the dangers in 2021, staff were not told for a year and safety measures were not introduced for another year.

An independent review two years ago by the Good Governance Institute (GGI) found there was an "unacceptable delay" by the trust in response to concerns about dangerous levels of the gas.

It concluded midwives and other staff on the maternity unit were "exposed to unnecessary risk or potential harm" and that high levels of gas on wards "needed to be treated as a significant risk to health" when concerns were raised in July 2021, but this was not done until October 2022.

Unstable leadership and management across different hospital departments added to the delay and the ineffective management of the problem, the GGI reported.

Poet says air monitoring in the summer of 2021 identified the workplace exposure limits were being breached, but it was a chance discovery the following year that led to department staff finding out.

He says workers should expect to be informed and the issue fixed, but the trust "sat on that document".

"It was only by coincidence that in October '22 there was some follow-up air monitoring that mirrored the original readings found on a manager's desk [and] that this all came to light.

"How long would this have gone on had it not been you know uncovered at that stage?

"These women had a pretty horrendous time for 18 months, possibly longer, in terms of the neurological effects, whether it's regular headaches, brain fog, chronic fatigue, dizziness, depleted B12.

"It was entirely preventable, and the trust knew about it."

The RCM stresses that gas and air is safe for women to use for pain relief during labour as the case was about the conditions midwives were working in, not the gas itself.

Gill Walton, the RCM chief executive and general secretary, says it is "imperative" that NHS buildings, fixtures and fittings are invested in to "prevent this from happening again".

She says the RCM has worked directly with the Health and Safety Executive (HSE) to update and improve guidance on the use of Entonox.

It has also written to every NHS trust in England to make them aware of the risks of the gas.

"The maternity estate is very poor - not just in Basildon but in other areas as well - and poorly maintained equipment, poor ventilation meant that those leaks were having a serious impact on the health of midwives working in the unit," says Walton.

"Maternity falls to the bottom of the list for investment all the time and there are crumbling maternity hospitals all around the country, and that's part of the problem."

In guidance issued to trusts in 2023, NHS England says staff exposure to nitrous oxide should be regularly assessed and monitored, and that hospitals should consider specialist ventilation and air purification systems - known as scavengers - to minimise risks to maternity staff.

The guidance says trusts should carry out risk assessments in any area where gas and air is used and ensure staff are trained and aware of monitoring results.

NHS England said the effectiveness of these measures should be assessed via regular air quality monitoring.

According to the Department of Health and Social Care, Mid and South NHS Essex NHS Foundation Trust, which covers Basildon University Hospital, was allocated £8.6m from the estates safety fund in 2025/26, with a further £4.7m over the next few years.

This covers building safety works, including new air handling units and other schemes identified by an NHS trust as priorities.

NHS Resolution, which manages legal claims and compensation cases on behalf of the NHS in England, confirmed the payouts for 121 workers.

On Tuesday, in response to the BBC's questions, it says its latest data shows it has paid £172,510 in legal costs in relation to this group of claims as of mid-August.

"This figure is not final and may increase as outstanding matters are resolved," it adds.

One claim still has to be settled in the group action, according to the RCM.

Scavenger equipment is now being used at Basildon University Hospital to purify the air at the maternity unit.

In a previous statement, Louise Crosby, the chief nursing and quality officer at the trust, said: "We have acknowledged that we should have acted faster to address the issues and have apologised to staff.

"Since the incident we have learnt lessons, and as part of this, we have improved our oversight of the monitoring of medical gases across the maternity unit at Basildon Hospital."

Additional reporting by Matt Precey.

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