A care home where some staff did not wear face masks or wash their hands when in contact with residents has been placed in special measures.
The Care Quality Commission (CQC) said it inspected The Limes in Hinckley, Leicestershire, in June after being contacted by whistleblowers.
It found less than half the staff had received specific Covid-19 training.
Leicestershire County Care, which runs the home, said issues were being acted on with the “utmost urgency”.
Following a previous inspection in January, the CQC found the home for dementia patients required improvement.
But inspectors have now deemed it inadequate, and last month placed it in special measures.
If conditions do not improve in time for a follow-up inspection in six months, the home could be forced to stop operating.
The CQC said its visit in June followed reports from staff members who “had no confidence in the provider listening to them or taking action”.
During the visit inspectors observed some staff “did not always follow effective hand washing or any hand washing between contact with different people”.
The report added: “Staff did not always wear the protective personal equipment such as face masks when in direct contact with people.”
This, inspectors said, put vulnerable residents at an increased risk during the Covid-19 outbreak.
Training records identified that “only 46% of staff had received specific Covid-19 training”, with “not enough staff to meet people’s needs or keep them safe”.
The CQC added that on occasion there were only four care workers between 34 residents, when many required at least one carer to every two patients.
Staff told inspectors they often left work feeling “stressed and worried”, knowing they had not completed all the tasks they should have.
Staffing concerns come after Leicestershire County Care Limited threatened to make about 100 care home staff redundant, in a dispute over pay and conditions.
In May, the care home operator served staff dismissal orders and offered care workers less favourable contracts, in a bit to cut costs.
The company said it was “very disappointed with the outcome and that our high care standards had not been achieved”.
It added it was working with the CQC and Leicestershire County Council to “improve and maintain safety and wellbeing of our residents”.