IndyCar defending champion Will Power’s fears have been realised with the death of “fantastic human” Justin Wilson.

The popular 37-year-old English driver died in hospital on Tuesday from a severe head injury sustained when struck by a piece of debris during the weekend’s race at Pocono in Pennsylvania.

The father of two’s death sent the motorsport community into grief, with Power leading the tributes as he once again dealt with the death of a colleague.

“So distraught to hear the news of Justin’s passing,” Power tweeted.

“He was such a fantastic human being & will be dearly missed.”

Power has long been an advocate for safety in the IndyCar championship, which has always struggled to balance its extreme high speeds and close pack racing with driver welfare.

The Australian was one of several drivers involved in the pack crash which claimed the life of another Englishman, Dan Wheldon, at the 2011 season finale in Las Vegas.

Wilson is the first IndyCar driver death since Wheldon’s but concerns had been aired about perceived lagging safety standards through the year.

The re-emergence of pack racing situations caused several drivers – including Power – to speak out after fellow Australian Ryan Briscoe survived a high-speed flip during the June race at California’s Auto Club Speedway.

Three airborne incidents in the build-up to this year’s Indianapolis 500 also raised concerns.

Canadian driver James Hinchcliffe was lucky to survive a crash at the Indy 500 this year, when a suspension part pierced his legs and severed an artery.

Hinchcliffe underwent emergency surgery and said he received more than six litres of blood en route to the hospital.

“We just don’t need another incident like we had in Vegas and running like this it will happen,” Power said in June.

“It’s just a matter of time.”

Wilson’s fatal crash was a freak accident, similar to that which nearly claimed the life of Brazilian Formula One driver Filipe Massa in 2009, rather than a pack incident.

His head was struck by debris from Sage Karam’s car after his vehicle had spun and hit a wall late in the 200-lap race.

Regardless of the circumstances, the tragedy is sure to put IndyCar’s safety under the spotlight aGain ahead of this weekend’s season grand final in Sonoma, California.

Wilson is the 107th IndyCar driver to die in either race or practice situations since 1916, the fourth since the turn of the century.

US auto racing legend Eddie Cheever told AFP that Wilson’s death should lead to a thorough analysis of safety measures in the sport,while acknowledging the freak nature of the accident.

“I think that it is time solutions are looked for and I think it is time the drivers got together and came up with a few ideas and I sincerely hope some progress will be made on this issue,” Cheever said.

“Safety is a continuous project and in the past IndyCar has done a very good job of doing it. But this is something they are going to have to focus on more than they have done in the past.”