OSSA’s extensive track record in the world of underground works has allowed it to accumulate a great wealth of experience in all aspects of this kind of work. OSSA’s experienced personnel are fully capable of handling the most complex projects involving installations in underground works: lighting, electrical systems, safety systems, ventilation, etc. Among them it is worth highlighting the waterproofing works that OSSA carries out through its affiliate HISISA. In addition, OSSA provides technical assistance to companies and entities requiring support in the execution of underground projects.