Threats and violence are acute safety issues in many industries and effect a large proportion of the Swedish workforce. In the construction industry, more than half of constructions workers redirecting traffic at construction sites are subjected to threats or violence at least once a year. To help construction companies to systematically address and handle health and safety issues in accordance with the Provisions of the Swedish Work Environment Authority on Systematic Work Environment Management, an interventions method named Building Health has been developed by Gyllensten and colleagues. The intervention involved rule-oriented and participative leadership practise and was evaluated through a single case effect study in a middle-sized construction company. The results showed significant reductions in the one-year prevalence of threats of violence (pre-intervention = 35.0%; post-intervention = 19.0%; χ<sup>2</sup> = 7.047; p = .008), feelings of being threatened (pre-intervention = 42.7%; post-intervention = 23.8%; χ<sup>2</sup> = 9.188; p = .002), and conflicts with third parties (pre-intervention = 48.5%; post-intervention = 30.6%; χ<sup>2</sup> = 7.913; p = .005). Combining rule-oriented and participative leadership when helping construction companies to improve their systematic work environment management for efficient handling of health and safety issues can have substantial positive effects on employees’ work environment.