Proof of employment with Q clearance at Bendix 1970's

I need proof of employment at a DOE site, Bendix, Kansas City Plant in the 1970’s.
I had a Q clearance during this time. Who do I contact for this information?

Why do you need proof? Any records needed for a clearance from previous investigations comes from the government. Why would you need an employment record 50 years ago?

I have applied to the D.O.E for compensation under the EEOICPA. I have Beryllium Sensitivity and Beryllium Disease that was most likely as a result of working inside the Bendix KC plant.
I worked for an outside construction contractor who is not listed on the DOE contractor list. We have SS records that match the time frame, but DOE can’t find a contract between the contractor and Bendix KC. I also have affidavids from co-workers stating that these facts but this is not satisfactory.

DOE Headquarters FOIA Request Form | Department of Energy

This site looks more hopeful.
Thanks HR2C

Proof of Q clearance turns out to be a dead end. NNSA does not keep records that far back. I have been denied 3 times now from DOE. What they say I need now is proof that the construction contractor that I worked for actually had a contract with Bendix KC Plant. I have 6 affidavits from co-workers stating this fact. The contractor that I worked for is not on the DOE list. Apparently, no one keeps these records either. Does anyone have any suggestions?