Hi Dan (and all)
Sometimes we shouldn't be looking to find a regulation or standard. The difficulty, if we follow these to the letter, it may not give us a strong enough defense for the employer.
I think we need to look at the hazards and in the use of a steering ****, I've listed a number.
As a foundation to an employer's due diligence, I still believe they should request something for their file from the manufacturer or an authorized dealer that use of a steering **** is a permitted use. Without this, depending on the injury and all factors, I believe an employer could be looked at as altering or modifying the steering and if this was the cause or a contributing factor, the employer could be charged.
Now, I could be stretching it, but.....if an employer is to take "all the precautions" and throw in the words "reasonable" and "adequate" I would hope all would agree that without documentation, the employer is at risk.
Dan, you are right that one needs to look at all the factors: is it an older truck without power steering? Does a driver not have use of one arm or hand?
I would highly recommend if a steering **** is to be used, that: one person does not make that decision. If you have a safety committee, take the question to them for a "company" decision.
Very best to all