tunnel worker examines pipeline in underground tunnel

abandoned builder channel chemical collector concept concrete danger dark dirty draining duct ecology engineering environment equipment fixing fixture fixturing gas heating helmet human industrial industry inside inspector interior job junk labor lantern light man metro mounter occupation person personel pipe pipeline pollution professional protection protective repair respirator river round safety service sewage sewer sewerage sinker smelly stinky subway suit surface tube tunnel tunneller underground undergroung uniform urban wastewater water work worker