For the first 10 days of May, Patagonia will donate $10 to the Mountains-to-Sea Trail for every pair of their footwear purchased through Great Outdoor Provision Co.

That’s a generous corporate donation, though not a surprising one from a company that has long abided by a bottom line that differs significantly from that observed by much of the corporate world. Patagonia is a company that in the mid-1990s hired third-party auditors to inspect its suppliers, a practice that’s only become common recently among mainstream retailers. A company that would just as soon you not buy their stuff unless you really, really need it, going so far as to take out ads on Black Friday — the high holy day for retailers — in 2011 proclaiming “Don’t Buy This Jacket.” A company that has gotten uber-retailer Walmart on board to sell environmentally responsible clothing.

Patagonia: A style as timeless as it is durable.

If you’ve ever picked up a piece of Patagonia apparel in the store, looked at the price tag and thought, “Hmm …” , remember one thing and do another:

1) The privately-held Patagonia (owned by founder Yvon Chouinard and his wife) has long been a leader in socially responsible business practices — practices that haven’t been widely adapted throughout the retail world because they cost money.

2) Go home to your gear closet, fetch something with a Patagonia label and try to remember how long you’ve had it. (“Holy cow! I remember wearing this fleece on a road trip to the mountains driving my new Gremlin!”)

Patagonia, which celebrates its 40th anniversary this year, began when a California rock-climber decided he wanted better climbing equipment than was currently available. Yvon Chouinard bought a coal-fired forge, taught himself to blacksmith and soon was producing top-notch pitons and carabiners. But it wasn’t until he started importing apparel — first rugby shirts and corduroy knickers for his climbing buds, later fleece vests that became the rage among New York fashion models — that Patagonia took off as a company. A company Chouinard didn’t really want in the first place.

“I never even wanted to be in business,” Chouinard told the Wall Street Journal in 2012. And, at age 74, he still doesn’t. “… I hang on to Patagonia because it’s my resource to do something good. It’s a way to demonstrate that corporations can lead examined lives.”

No U.S. company examines itself like Patagonia.

That approach dates back to at least 1988, when Patagonia opened a retail outlet in Boston. Within the first few days, all the employees at the store became sick. Engineers discovered the ventilation system was recycling the same air over-and-over. But what was in the air that was making everyone sick? Patagonia wanted to know.

Formaldehyde, it turned out, sprayed on the cotton used in its apparel.

“This lead us to commission a study of conventional cotton, and the discovery that cotton grown with pesticides is one of the most destructive crops in the agricultural world,” Patagonia writes on its website. “Knowing what we knew, we could not continue to use conventional cotton for our sportswear. We went organic in 1996.”

Organic Cotton – Grown in the USA from Patagonia on Vimeo.

Examining one’s corporate self isn’t always easy — “Living the examined life is a pain in the ass,” says Chouinard — but it does put the customer’s mind at ease. Among Patagonia’s other efforts toward corporate responsibility:

• Creation, with Walmart, of the Sustainable Apparel Coalition, encouraging major brands and retailers to adapt clear, quantifiable standards for producing environmentally responsible clothing. In addition to organic cotton, Patagonia uses recycled and recyclable polyster and hemp in its products.

• Donating, since 1985, more than $41.5 million — 1 percent of annual revenue — in grants and in-kind donations to grassroots environmental organizations. During that time it has convinced more than 1,400 other companies to join its “1% for the Planet” initiative.

• Created, with eBay, Common Threads, the aforementioned program designed to get people to buy and sell used gear rather than buy new. It’s part of their 5Rs pledge: to Reduce consumption, Reuse old gear, Recycle gear, Repair gear rather than toss it, and Reimagine a world that places less of a burden on the planet through consumption.

• Adopted a comprehensive program to ensure that its products are produced fairly and under humane conditions. To this end, Patagonia began contracting with third-party auditors nearly 20 years ago to inspect the factories that produce its apparel and gear, and was a founding member of the Fair Labor Association.

• In 2002, created a Manager of Social Responsibility position, which in 2010 was elevated to a director post — Director of Social/Environmental Responsibility.

• Toward the goal of being socially and environmentally responsible, created The Footprint Chronicles on its website, which lets consumers track the origin and creation of each Patagonia product.

Patagonia’s offer to donate $10 for every pair of its shoes purchased expires May 14.