A senior doctor has raised concerns about the use of scan vans targeting Devonport Dockyard.
The company has been deliberately targeting dockyard workers
The vans offer CT Scans to men who have worked with asbestos to see if they have a medical problem they can claim compensation for.
The company offers the free scan on the understanding that if an abnormality is picked up a lawyer will put in a claim for compensation on their behalf.
The company said all procedures were in full accordance with regulations.
FreeClaim IDC - which advertises in the local newspaper - say the procedures are supervised by senior and eminent consulting radiologists.
Consultant Chest Physician at Derriford Hospital Dr Clive McGavin said he could see no advantage in picking up asbestos related pleural plaque early as it is benign while the more serious cancer is treatable.
He said: "The CT scan requires a lot of radiation.
"The patient is then told he may or may not have some completely harmless asbestos scarring but he is also told he has some sort of shadow which may or may not be lung cancer.
"Commonly we will give a further scan to see if the shadow has increased in size or remained the same three or four months later.
"The man may well be significantly worried and furthermore the second scan will involve more radiation."
In a statement FreeClaim IDC said: " All procedures are in full accordance with all relevant regulations.
"These procedures are supervised by senior and eminent consulting radiologists. With regards to levels of radiation flying across the Atlantic exposes a normal person to about the same dose as a CT scan of the chest."