Too many trusts are still not responding to patient safety alerts in England, campaigners say.
Alerts are issued when potentially harmful situations are identified in health settings, such as the risk of overdoses or using medical equipment.
Department of Health data showed there were over 650 cases of NHS trusts not complying with alerts within deadline.
This is a 50% fall from last year, but Action against Medical Accidents said there was no excuse for non-compliance.
The charity first highlighted the issue last year when it obtained the figures under a freedom of information request.
But now the government has started publishing the figures itself.