The NEMO project is exploring the use of mobile sensor nodes toaugment physical work artefacts in order to ensure compliance with health and safety regulations. In this paper we present our experiences of designing and deploying the NEMO Hand Arm Vibration (HAV) monitoring system. Long term exposure to hand arm vibration can lead to serious health conditions and the NEMO HAV monitoring system offers an integrated architecture for capturing HAV exposure data in the field, providing feedback about exposure levels both in the field and as input to a back-end database. Our design allows health and safety regulations specified at the enterprise level to be embedded within the wireless sensor nodes allowing them to operate without any infrastructural support. The system has been the subject of a two week field trial that took place with the collaboration of a British construction and maintenance company. During the field trial, the NEMO HAV system was deployed to a roa dmaintenance patching gang and data were collected on HAV exposure caused by hydraulic drills. The paper reports on the results of the field trial and the lessons learned through the real deployment of the system.