The measures, described as "a recipe for confusion", are contained in the deregulation bill currently going through parliament. They arose from recommendations by Professor Ragnar Löfstedt in his government-commissioned review of health and safety in November 2011.
At the time Löfstedt proposed "exempting from health and safety law those self-employed whose work activities pose no potential risk of harm to others." The report also proposed a list of activities that should not be exempt.
But the current wording in the bill has been changed to exempt all self-employed people unless they are on a prescribed list.
Hugh Robertson, TUC senior policy officer, said: "This means that if they are not on a prescribed list, even if they injure or kill someone, they will not be able to be prosecuted under the HSW Act.
"This is not what was proposed in the Löfstedt report, or what the Health and Safety Executive consulted on."
The prescribed list drawn up by the government will be subject to consultation. Robertson said the current list excludes huge groups of self-employed people in dangerous occupations. Among them are those working in the entertainment industry building sets, vehicle repair, haulage, people in docks, and almost all of manufacturing.
"Even those areas that are covered are hardly clear. Construction, for instance, makes no reference to those working in people's homes, such as plumbers, carpenters and electricians."
Danger to others
Robertson pointed out that the HSE had never prosecuted a self-employed person who killed or injured themselves. "It is the danger to others that the HSW Act has tried to control, not only of death, but also occupational diseases and injury.
"Under the new proposals anyone not on the list will not be able to be prosecuted if they kill or injure someone, however negligent they are."