Political decisions about the way that public health initiatives are implemented have a significant impact on the ability to evaluate their effectiveness. However, the influence of the political imperative has been little explored. This case study of key research, policy and practice events concerning one initiative, exercise referral schemes (ERSs), demonstrates that these schemes were encouraged to expand by the Department of Health (DH) before DH-funded evaluations had reported their findings and with little reference to National Institute for Health and Clinical Excellence (NICE) recommendations. Policy evolved in parallel rather than in conjunction with the development of evidence, and experimental evaluations in England are now unlikely. This is due to the comprehensive coverage of schemes, widespread assumptions of effectiveness, likely difficulties in obtaining research funding, indirect adverse consequences of dismantling schemes and lack of appropriate process and outcome data. Embedding a commitment to robust evaluation prior to universal adoption of new initiatives has been shown to be feasible by policy-makers in the international setting. This is required to prevent the establishment of public health interventions that do not work and may cause harm or widen health inequalities.
current blood lead concentrations, and that the ALAD-2 genotype may be an additional modifier of this effect (Smith et al., 1995). The Carpenters have also worked with Dr. Selikoff's successors, a network of devoted scientists, by promoting continued study of the membership.
These studies demonstrate that information useful to workers' health can be obtained when workers and unions collaborate with their scientific and academic colleagues. By providing additional evidence of lead's toxicity at very low blood and bone levels, such studies can promote changes in occupational standards that better protect the health of workers.
Occupational and Environmental Regulation
Numerous standards have been set for lead in both the occupational and nonoccupational setting. Some standards set limits on allowable concentrations of lead in the ambient air or workplace air, as well as other environmental compartments, and some standards are based upon biological monitoring. In the workplace, both airborne lead and biomarkers are components of preventing lead poisoning in most national systems.
The U.S. occupational lead standard was promulgated in 1978, one of the first de novo standards developed by the Occupational Safety and Health Administration (OSHA), without reliance on earlier guidelines proposed by the American Council of Government and Industrial Hygienists (ACGIH). the OSHA lead standard was noteworthy in that it proposed both a limit on airborne lead in the workplace (50 microgram/m3) and a mandatory program of biological monitoring in most work settings. In addition, the OSHA standard protected worker health and employment rights by establishing a medical removal program: workers whose blood lead levels exceeded the standards were temporarily shifted to jobs without lead exposure with no loss of pay, benefits, or seniority. This approach was intended to change the incentives in the labor management relationship, to encourage employers to reduce lead exposures, and to protect workers from job termination or loss of income.
In the United States, occupational standards cover most, but not all, workers exposed to lead. In 1993 the lead standard was finally extended to workers in the construction industry, who are often highly exposed to lead during repair and maintenance of steel structures (which may still be painted with lead-based paints); demolition workers; and workers involved in abating lead hazards in housing. Small workplaces are still imperfectly covered, and some of these, such as battery repair shops, may be sources of intense exposure that not only pose problems for workers, but