All 40 workers trapped after an under-construction tunnel collapsed in Uttarkashi are safe and communication has been established with them, officials said on Monday as Chief Minister Pushkar Singh Dhami reached the site to oversee rescue operations. Rescuers who worked overnight trying to prepare an escape passage for the labourers have provided them with food and water, the Silkyara police control room said. A portion of the tunnel being built between Silkyara and Dandalgaon on the Brahmakhal-Yamunotri National Highway caved in on Sunday morning.