Shrewsbury and Telford Hospital NHS Trust's quality and safety assurance committee recently visited the A&E department at Royal Shrewsbury Hospital.
A report to the trust board notes that progress has been made in respect of the recruitment of A&E consultants, but says there are still considerable strains on the workforce.
It said: "The two A&E departments are surviving on the extreme commitment of SATH staff and their impressive resilience.
"There have, however, been recent resignations from the nursing staff and reports that on many nights there has not been a registrar doctor working to support nursing staff and more junior doctors.
"The committee were not assured that this is a sustainable position."
SaTH's chief executive Simon Wright says over the next four weeks the trust will be looking again at its A&E business continuity plan and will consider the current risks it faces.
There has been a risk that Telford's A&E may have to temporarily close overnight on safety grounds.
There are still large gaps in consultant and middle grade doctor cover, against recommendations made by The Royal College of Emergency Medicine.
Heath bosses say nurse staffing levels are also a concern due to the level of temporary and permanent vacancies resulting in increased agency cover and unfilled shifts.
SaTH's workforce committee has also recognised the high levels of stress and pressure being put on staff.
The committee has been gathering information about the experiences of staff in the workplace by looking at sources such as a staff survey and leavers questionnaires.
A report by Chris Weiner, chairman of the workforce committee, says: "There are significant levels of stress and pressure upon our staff whilst they are attempting to continue to deliver high quality care to a large number of patients, often with less than ideal numbers of permanent staff."
It says the staff survey has revealed one in four staff say they have experienced bullying or harassment at work.
Mr Weiner said: "This is unacceptable and not the experience we want for our people, ourselves or those wider members of our community that will inevitably feel the impact of stressors on our staff.
"The committee are deeply concerned by this feedback.
"The committee has acknowledged that this is how staff feel, has then sought to better understand this through a series of staff engagement events and has then developed its response.
"The committee now wish to ensure that this matter is addressed."
An action plan has been drawn up to try and address the issues and the committee says it will continue to seek assurances on the delivery of a better working environment for staff.