My husband has gone blind we believe it is due to people welding around him at work, is this a possible cause?

Unlikely. It is unlikely but not impossible. If your husband has gone blind i recommend he get an evaluation from a qualified ophthalmologist as soon as possible.
Welding risk. Being exposed to welding is an exposure to ultraviolet light. This most commonly causes "flash burn", which is corneal damage. Although painful, the damage is superficial and the cornea will usually heal without scarring. Even bystanders can be flash burn. Cataract and retinal problems have been associated with sun exposure, but it is uncertain if welding exposure would cause these.