A special needs school, which was forced to close after two teachers tested positive for coronavirus, is yet to reopen.
Thornbury's Sheiling Special School shut it doors on May 11 as other members of staff were reportedly showing symptoms.
National Education Union representatives claimed they had been raising concerns with school chiefs for 'some time about a lack of PPE, deep cleaning and testing'.
But the school said it had "rigorous" measures in place - including the use of PPE and daily cleaning.
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Union bosses have now been working with school leaders to plan a safe way for teachers and staff to return to the building.
A NEU spokesperson said: "The current situation is that the school has closed and will only reopen when they are certain that the environment is safe for students and staff.
"They have been very open to working with NEU staff reps and members alongside the South Gloucestershire officers to find a positive outcome for all."
A spokesperson for the school previously said a 'deep clean' would be conducted at the building and all members of staff and pupils would be tested for Covid-19.
School leaders are now working closely with Public Health England, South Gloucestershire Council, teachers and their union representatives to plan a 'safe reopening'.
The residential homes for children and young people that are run by Sheiling School have been unaffected by the cases and remain open.
