WASHINGTON (Reuters) - President Barack Obama has ordered his administration to offer health insurance to seasonal firefighters employed by the U.S. government, after an outcry over the lack of affordable coverage available to thousands of such workers.

Obama's directive, confirmed by the White House on Tuesday, capped a 2-month-old electronic petition drive started by a member of a U.S. Forest Service "hot-shot" crew based in South Dakota that has drawn more than 125,000 signatures.

No details were given, but a formal announcement of the policy change was expected soon, a White House official told Reuters.

In the meantime, Obama has instructed the U.S. Office of Personnel Management, the Interior Department and the Agriculture Department -- parent agency of the Forest Service -- to "ensure temporary federal firefighters who are bravely battling fires have access to the health insurance they deserve," the official said.

The official added that the president acted after the issue was brought to his attention following his trip late last month to Colorado Springs, Colorado, where Obama toured damage caused by that state's most destructive wildfire on record.

The so-called Waldo Canyon, which broke out June 23, killed two people and gutted nearly 350 homes and forced the evacuation of some 35,000 people. Ranked as one of worst conflagrations to date during the 2012 wildfire season nationwide, it was finally declared 100 percent contained late Tuesday.

At that time, the White House said that more than 8,800 firefighters were at work against dozens of wild-land blazes burning across the country, most of them in the West.

Some 15,000 firefighters are on the federal government payroll, but 8,000 of them are classified as temporary, seasonal employees and thus ineligible for federal benefits such as health insurance, according to Rachel LaBruyere, an organizer of the petition drive on the nonpartisan social action website Change.org.

"It's a huge deal, and there's going to be a lot of really, really happy firefighters out there tonight," said John Lauer, 27, seasonal member of a "hot-shot" crew from Custer, South Dakota, who initiated the petition drive seeking health benefits. "I'm sure they're all very thankful for what the president's done."

Lauer, who resides in Denver and has never had health insurance during his six years of employment for the Forest Service, said seasonal firefighters like himself typically work the equivalent of an entire year during a six- or seven-month rotation.

"The seasonal firefighters, they're the ones digging the trenches, cutting trees down, actually putting the fire out on the ground, and they're the ones breathing the smoke," he said.

On-the-job injuries have been covered by workman's compensation under the old policy, he said, but "if I got bronchitis in the winter because I inhaled smoke for six months, that wouldn't be covered."

In the text of his petition, Lauer cited the case of a fellow firefighter who accumulated $70,000 worth of hospital bills that he and his wife were unable to pay after the premature birth of his son.

(Reporting by Matt Spetalnick in Washington; Additional reporting and writing by Steve Gorman; Editing by Tim Gaynor and Lisa Shumaker)