I've been reading along, but haven't expressed any opinions yet. OSHA 1910.179, 1910.180, 1910.181 deal with material handling(cranes).
Here is what OSHA 1910.179(l) Maintenance has to say----(1) Preventative maintenance. A preventative maintenance program based upon the crane mfg's recommendation shall be established.
1910.179(l)(3) Adjustments and repairs. (i) Any unsafe conditions disclosed by the inspection requirements of paragraph (j) of this section shall be corrected before operation of the crane is resumed. Adjustments and repairs shall be done only by designated personnel.
Definition: (1910.179(a)(35) Designated means selected or assigned by the employer or the employer's representative as being qualified to perform specific duties.
I read this to say that the employer is taking on the responsibility to ensure that the designated personnel performing the welding is qualified to perform this task. Employer is on the hook if anything bad arises out of this situation at a later date.
If I was the employer, I would make darn certain that this designated person is qualified to perform this task.