Unions have condemned the "missed opportunity" to protect workers as a Bill designed to make it easier to prosecute companies after fatal accidents progressed through parliament.
The Corporate Manslaughter and Corporate Homicide Bill passed its crucial second reading last week and will now be debated in committee before coming to the Commons again.
The Bill proposes a new offence that targets serious failings in strategic management of a company's activities which lead to death. It fulfils a promise made to the unions under the 2004 Warwick Agreement, but they argue that it will not deter irresponsible employers as it targets corporate, rather than individual, liability.
The Transport and General Workers' (T&G) union and construction union Ucatt argue that unless specific health and safety duties are imposed on directors, the culture change needed to prevent deaths will not take place.
Tony Woodley, T&G general secretary, said: "Workers will ask us if this is the Bill they have been waiting nine years for from a Labour government, to protect them from negligent bosses. The answer is: 'No'. It hands negligent directors a 'get out of jail free' card and won't deliver justice or safer workplaces."
However, home secretary John Reid offered unions a glimmer of hope by promising to take objections seriously and to bring forward amendments in committee.
Unions claim that 2,475 workers have been fatally injured at work in the past 10 years, yet only 11 company directors have ever been convicted of manslaughter.