The game had looked like it was heading for a draw before defender Humphries smashed home from 20 yards to make it a good trip to Lancashire for Pool.
But the game turned on a spitting incident in the 71st minute when Jay Harris was sent off for Accrington for allegedly spitting on Hartlepool captain Michael Nelson.
At that stage Stanley were winning but Pool piled in the pressure on the ten men top secure the victory.
Pool manager Danny Wilson would have been happy with his sides start as both Jon Daly and Gary Liddle came close in the first 5 minutes.
However then Accrington came into the game with Ian Craney testing Pool keeper Dimitrios Konstantopoulos with a 20 yard free kick and also a curling corner which bounced just wide.
It was a scrappy game with few clear cut chances for both sides with Daly having a snap shot just wide and Liddle having another go but being blocked by Stanley keeper Ian Dunbavin.
Both sides were disjointed especially after both lost their right-backs to injury with Pools Darren Williams and Stanley's Peter Cavanagh hobbling off in the first half.
It needed a moment of magic to change the game and it came from Stanley's Andy Todd on 38 minutes. He latched onto Paul Mullins back heel, weaved his way into a good position on the edge of the area and fired low into the net for his 4th goal of the season.
Pool captain Nelson almost replied immediately but his thumping header was kept out by Dumbavin to give Stanley a first half lead.
Pool upped the tempo after the break although clear cut chances were again at a premium.
In fact the best one fell to Stanley on the hour when Todd played a ball in, Harris missed it completely and Mullin backed him up but touched the ball wide.
Then came the controversial sending off of Harris which changed the game. Within 5 minutes, Hartlepool were level. Richie Humphries effort was pushed behind for a corner and from it Stanley failed to clear their lines and substitute Effion Williams volleyed home from the edge of the area.
Pool could have doubled their lead soon after when James Browns superb volley hit the underside of the bar. Daly was first to follow up but Stanley defender Robbie Williams was alert to clear off the line.
However, the reds defence let Humphries charge into the area a minute into injury time and he unleashed a fierce shot from 20 yards which tucked low into the bottom corner of the net for the winner.