ORIGINAL ARTICLE The effect of human capital on occupational health and safety investment: An empirical analysis of Spanish firms Imanol Nuñez 1 | Maite Prieto 1,2 1 Business Administration Department, INARBE—Universidad Pública de Navarra, Pamplona, Spain 2 Technical Department, Vivienda y Suelo de Euskadi, S.A., Vitoria, Spain Correspondence Imanol Nuñez, Business Administration Department, INARBE—Universidad Pública de Navarra, Campus de Arrosadia, s/n, 31006 Pamplona, Spain. Email: imanol.nunez@unavarra.es Funding information Spanish Ministerio de Educación, Ciencia y Cultura, Grant/Award Number: ECO2017‐ 86054‐C3‐2‐R Abstract This paper analyses how firms' human capital influences their investments in occupational health and safety (OHS). We argue that the incentive to protect workers by investing in OHS is a function of the stock of human capital. The empirical analysis was based on data from the official Working Condi- tions Spanish Survey on OHS management. Our sample was restricted to 1,472 firms from the manufacturing and con- struction industries. Our results show that firms that place more emphasis on training and have a multiskilled and inno- vative workforce invest more in OHS. However, having tech- nological and design skills has no impact on the investment in OHS, presumably because these skills are widely available in the labour market. Finally, the analysis suggests that some abilities such as problem solving may be affected by informa- tional asymmetries and therefore firms may suboptimally invest in protecting these capabilities. KEYWORDS competitive advantage, human capital, management, occupational health and safety 1 | INTRODUCTION The relationship between skills, effort, and workers' health has attracted the attention of the most prestigious econ- omists from the very beginning of the discipline. Adam Smith (1776), for example, in the Wealth of Nations stressed that “mutual emulation and the desire of greater gain frequently prompted them (workers) to overwork themselves, and to hurt their health by excessive labour.” To control the effect of work effort on health, the International Labour Organisation (ILO) and the World Health Organization jointly established that the first and foremost objective of the occupational health and safety (OHS) policies should be the “maintenance and promotion of workers' health and Received: 28 July 2017 Revised: 5 June 2018 Accepted: 13 July 2018 DOI: 10.1111/1748-8583.12208 Hum Resour Manag J. 2019;29:131–146. © 2018 John Wiley & Sons Ltd wileyonlinelibrary.com/journal/hrmj 131