An oil platform has been evacuated after a ship carrying radioactive material caught fire and began drifting in the Moray Firth.
The MV Parida was transporting a cargo of cemented radioactive waste when a fire broke out in a funnel.
The blaze was extinguished, but 52 workers were taken from the Beatrice platform by helicopter as a precaution.
By 22:00 on Wednesday, the ship had been towed to a "secure pier" at the Port of Cromarty Firth.
Its 15 crew were not harmed during the fire and it was understood the cargo was not damaged.
Ministers said the Scottish government was "closely monitoring" the incident.
Dounreay Site Restoration Limited has confirmed the waste was from Dounreay, an experimental nuclear power plant near Thurso which is being decommissioned.
The material, which was sent to Dounreay from Belgium for reprocessing in the 1990s, was being shipped back to Belgium.
The Nuclear Decommissioning Authority (NDA) said the Parida was carrying two containers called flasks each holding three 500-litre drums of intermediate level waste.
The NDA said the ship and its cargo had been categorised at the lowest level of safety concern.
It described Tuesday night's event as a "marine incident and not a nuclear incident".
The coastguard were alerted at about 20:00 on Tuesday as the Danish registered Parida was taking a cargo of radioactive concrete from Scrabster to Antwerp in Belgium.
The platform staff were flown to RAF Lossiemouth shortly before midnight. Parida was about seven miles from the Moray Firth platform at the time.
Dounreay's nuclear waste
- In 2011, it was announced that more than 150 tonnes of intermediate level waste would be transported back to Belgium in 21 shipments over the next four years. The Belgian material had been at Dounreay for reprocessing, but is being returned because the Scottish site is being decommissioned and demolished.
- Also in 2011, bosses at Dounreay started discussion on the return of several hundred tonnes of waste to customers in Australia and Germany.
The BBC Scotland news website's Highlands and Islands reporter Steven McKenzie has been looking at how Dounreay's toxic leftovers are being handled.
Environment Secretary Richard Lochhead said the Scottish government was "closely monitoring" the incident.
He said: "Most people, like me, may not be comfortable with the idea of a vessel carrying nuclear waste waiting for a weather window to sail through our waters.
"While these vessels are built to cope with extreme weather, if they break down they drift and that is a fact we have to think about here.
"It is a serious incident and I think we need to review how we regulate the transportation of nuclear waste in our waters. That is the responsibility of the Office of Nuclear Regulation and I will be speaking to UK ministers about it."
WWF Scotland, Comhairle nan Eilean Siar and SNP MSP Rob Gibson have raised concerns about radioactive waste being transported by sea.