But after turning two previous penalty appeals aside, referee Mike Pike finally pointed to the spot in stoppage time after the Northern Ireland striker tumbled under the most innocuous of challenges by fellow countryman Steve Lomas.
That led to furious scenes at the final whistle and after seeing the gritty Yorkshiremen secure a point to pull off the biggest heist in London since the Brinks Mat robbery, an incensed Alan Pardew did hesitate to call it a 'desperate dive'.
West Ham had come into this game boasting back-to-back wins over Watford and Sunderland while Leeds had suffered successive losses at the hands of Rotherham United and Leicester City.
And on a chilly East End night under the Upton Park floodlights, Pardew's men would have been well on their way to a hat-trick of victories had Neil Sullivan not spectacularly fisted Sergei Rebrov's stinging, third-minute, 20-yarder skywards.
But the Ukrainian's effort was to prove a false first-half dawn. For facing a three-timer of their own, Kevin Blackwell's men soon demonstrated that they were equally determined to avoid a trio of pointless performances.
Indeed, it was not long before ex-Hammer Brian Deane was racing on to on-loan Darren Powell's underhit backpass and sending an angled 20-yard curler over the stranded Stephen Bywater and against the Hammers' crossbar.
Healy then forced the Hammers keeper into two brilliant saves and as interval neared, referee Pike waived away Danny Pugh's first penalty appeal after he ran across Anton Ferdinand.
Then Sean Gregan almost got himself back into the favour of the Elland Road boo boys with a low 18-yarder which Bywater did well to claim as it scorched through a pack of bodies.
Frustrated by his side's attacking impotence, Pardew replaced Rebrov with Teddy Sheringham at the break and within five minutes of the restart they had found the net.
Matthew Etherington's left-wing cross was met by Marlon Harewood whose close-range header ricocheted off Matthew Kilgallon down into the path of Chadwick and he scrappily bundled the ball over the line to give West Ham the lead.
Down but not out, Leeds' early attacking verve looked set to continue and on 55 minutes, the unmarked Deane somehow volleyed wide from eight yards after Healy cut the ball back into the goalmouth.
That looked destined to prove a costly miss, but two valuable Sullivan saves from Sheringham kept Leeds alive, and with showboating West Ham looking all set to celebrate that hat-trick of wins, they survived Darren Powell's handball only for Healy to take the suspicious stoppage time tumble that saw him salvage a point with a clinical penalty.