Cut at root and put herbicide there. Be careful removing because leaves that are dead can still contaminate you. If
isn't one.....you cannot even pull/dig it out and successfully remove it Round-Up.......cut if off,wearing mask & gloves and long sleeved pants & shirts, remove tops put in garbage bags( thoroughly wash clothing shoes tools anything that you have used to remove the tops) get 2 gallon pump sprayer(not a back pack don't risk leaking solution on your back) buy concentrate Round-Up add food coloring to it(so you can see where you are spraying it) as soon as you see new leaves growing on stems spray them heavily with the Round-Up. It is absorbed into leaves them stems then kills root systems. Round-Up works best when plant is in vigorous growth after being cut off & new leaves are emerging.Keep checking for new growth and spray thru out growing season.Depending how big the area is it may take a few weeks to get it all. Put spray nozzle down onto leaves when spraying & do not spray in wind or breezy conditions;use gloves;do not walk or get in wet solution. Follow the safety instructions on container they are & have always been on the container for a reason.
This article suggests that you can kill poison ivy with boiling water.
Just did this with my girlfriend. We dig it out, mark the bags for the refuse service, drown the area in agricultural strength vinegar. Then take a shower, then wash our clothes.