Investigation exposes hospital nitrous oxide failings

Staff at a maternity unit at Basildon Hospital in Essex were exposed to almost 30 times the legal workplace exposure limit for nitrous oxide, according to a BBC investigation.

Testing at Basildon Hospital revealed the levels more than 16 months before colleagues were informed. According to the BBC, the Royal College of Midwives has said its members there are now considering legal action.

Mid and South Essex NHS Foundation Trust has said, however, that “significant improvements” have since been made.

Routine testing of the maternity suite in June 2021 revealed nine staff members had been exposed to excess nitrous oxide levels during the course of their shifts.

Three had readings of more than 1,000 parts per million (ppm) of the gas, while a fourth recorded almost 3,000. The Workplace Exposure Limit is set at 100ppm. Trust management apologised after failing to notify staff at the unit until October 2022.

A briefing seen by the BBC stated the issue was logged on the risk register, but “there has not been proper oversight of the problem and staff have not been informed”.

Nitrous oxide gas, also known as Entonox, is used as a sedative for women during childbirth. Vitamin B12 deficiency is highlighted as one potential health risk arising from exposure to the gas.

It is understood that testing of staff for vitamin B12 levels began in October, with pregnant staff redeployed and specialist referrals for those who need it.

The Royal College of Midwives told the BBC: “We have been approached by midwife members who have suffered a variety of symptoms they attribute to exposure to Entonox.

“Basildon Hospital investigations have revealed the exposure levels in the maternity departments were over the legal limit.

“We are investigating these issues with our lawyers to support our members in potential claims and have reported the issues to the HSE who are also carrying out their own investigation.”

A spokesperson for Mid and South Essex NHS Foundation Trust also told the BBC: “We have followed all of the expert advice provided to us to deal with the issue of nitrous oxide in the air at our maternity unit at Basildon Hospital.

“Significant improvements have been made and it is perfectly safe for service users and their families to continue to use the maternity unit as normal. We have taken action to resolve the situation and an investigation is under way.

“Support and advice is being offered to our staff. Mitigations have been put in place, based on clinical recommendations, and we are continuing to keep our staff informed.”