A problem with foam used to provide buoyancy was at the center of two recent duck boat accidents in England that saw one tourist vessel sink and another catch fire.

The incidents — one in Liverpool in June and one on the River Thames in London in September — resulted in passengers, including small children, going into the water.

The Marine Accident Investigation Branch, which discussed both accidents in one report on Monday, is recommending that the vessels not be permitted to operate until the foam problem is sorted out, according to The (U.K.) Guardian.

“Both accidents resulted in the rapid abandonment into the water of passengers, including small children, and crew,” chief marine accident inspector Capt. Steve Clinch told The Guardian. “It was extremely fortunate that, on both occasions, there were no serious injuries or loss of life.”

“The results of the investigation into the fire indicate that the current method of inserting foam is not working, as it compromises the safe operation of the vessels,” Clinch said. “I have therefore recommended to the Maritime and Coastguard Agency that the DUKWs should not be permitted to operate until the required standards of buoyancy and stability can be achieved without adversely impacting on their safe operation.”