The one serious casualty caught in the blaze that gutted the team's garage at the Circuit de Catalunya, spent two nights in a Barcelona hospital before being flown back home on Tuesday.
Chief operational engineer Mark Gillan said: "I would like to reiterate our thanks to everyone in the paddock who helped the Williams team on Sunday to control the fire.
"There were a number of people who attended the circuit medical centre, mostly as the result of smoke inhalation.
"One team member remains in hospital having suffered burns, but he is in a stable condition and in good spirits and has returned to England for further medical care."
Gillan has confirmed investigations remain ongoing into the cause of the fire that started in the fuel area of the garage as team principal Sir Frank Williams was giving a speech following Pastor Maldonado's victory.
Despite the offer of help from a number of teams with regard to the loaning of equipment ahead of next weekend's Monaco Grand Prix, Gillan concedes the race will not be an easy one for the team.
"The extent of the damage is still being accessed and will not become fully clear until both the cars and equipment have returned to the factory," added Gillan.
"What is clear is that our garage IT equipment and infrastructure have been badly damaged.
"On the back of a win we go to Monaco with high hopes, but there is a prodigious amount of work to be done prior to the event to recover from the fire."