In the United States, foreign-born workers of Hispanic origin have been central to the construction industry for decades. Many of these workers have experienced only limited education in either English or Spanish and most are bilingual to some degree. As employers are beginning to recognise the benefits of providing access to the OSHA 10- and 30-hour Construction Safety Training Course, the industry has begun to experience a downward trend in preventable accidents, illnesses and fatalities. Despite this decline, a detailed review of recently published research indicates that foreign-born workers of Hispanic origin remain nearly 70% more likely to be involved in a work-related incident than their American-born counterparts. In order to develop and provide effective workplace learning programmes it is necessary to assess the impact which these workers’ literacy and confidence in a second language has on their professional capabilities. This problem is examined by utilizing a simple post-test only randomised experimental design to measure knowledge retention among this demographic immediately following the completion of OSHA 10-hour Construction Safety Training Courses when the languages of instruction were English-only, Spanish-only and both English and Spanish. The data revealed that workers who fall into this category retained more knowledge from the training course when it was taught using a translanguaging approach. This data will be of value to designers of workplace education programmes, who will be better placed to incorporate a bilingual element into their instructional methodologies.