Recently we have had a number of reports from a number of fitters reporting of skin on their hands, arms and some on their face has become red and itchy.
On investigation of the substances used, even the dry painted items they assembly we have identified no obvious culprit, nor have we identified any synergistic effect from use of multiple substances. Substances used are predominantly, Standard mineral oils, hydraulic oils and greases, Loctite for screw threads. We have looked at the dusts created from sanding painted areas; however the people affected wouldn't even come close to come into contact, although some will.
We have asked the usual domestic questions etc, including that all individuals washing their own overalls etc and live in different parts of the region.
On this basis, we are at a loss to identify what the cause is for the skin issues reported. Has anyone come across a similar issue to this in a mechanical assembly environment with the array of substances an environment like this uses?

You could have a look at the type of hand cleaner the workforce uses (try introducing barrier creams and some type of moisturising cream), do you have problems with pigeons? as their nests have small insects in them that irritate your skin, if so contact a pest control company who can carry out various tests to see if this is the case

Also look at gloves and other consumables - possible change of supplier or spec. which may have gone unnoticed - even on the finished parts they are routinely handling.

Doobrifurkin - If the work includes contact with nickel-plated components, it is possible that sensitivity to nickel might be involved. I've no direct experience of this particular cause, but do recall years ago seeing a video film about people developing such sensitivity through working in a large cash office for a public transport organisation. Their work involved handling large volumes of cash, including nickel silver coins taken as fares on buses and perhaps at railway stations as well.

As previous responders have indicated, identifying and dealing with occupational skin irritation is far from easy. One of my standard questions in vehicle repair garages during my decade with HSE was about skin irritation which could be provoked by contact with any of the various substances (oil grease, petrol, etc) which employees encountered. HSE training included the fact that a relatively small proportion of people react badly to even small quantities of such substances, with the result that wearing medical gloves or barrier creams was of little use and the only real protection came from ceasing to work with vehicles. This would be extremely bad news for garage apprentices who were learning the trade they had probably dreamed of doing. I didn't encounter any such people myself but recall that occasionally other inspectors and EMAS colleagues did.

Anyhow, hope the cause of the problem - and a solution - can be identified soon for the benefit and relief of the affected ermployees. As with other types of problems raised on this forum, if you are successful, it would be good if you could share with us the cause and solution/s in due course. This might well help others with similar situations as well as demonstrate just how constructive this forum can be at times.

p.s. The spell checker wasn't happy with your name and suggested "debriefing" as an alternative!