For quite some time, the pink box has become the signature container of pastries and doughnuts from Los Angeles to San Francsico.

Various brands in the region, considered by many as the doughnut capital of the United States, have embraced the uniform hue, although not many people really know why.

A recent investigation into the phenomenon, however, revealed that Asian immigrants were somehow responsible for the current doughnut box color of choice.

As noted in the report by L.A. Times, L.A. County alone already has 680 doughnut shops, a number that exceeds New York City stores by 200.

Dominated by small businesses, the doughnut industry in the area was reportedly influenced by Cambodian-American immigrants who fled the Khmer Rouge in the 1970s.

Why are doughnut boxes pink? The answer could only come out of Southern California https://t.co/6AsXc9PgZK pic.twitter.com/OlDSL4Mt83 — Los Angeles Times (@latimes) May 25, 2017

The pink box, according to the report, can be traced back to Ted Ngoy, the owner of several doughnut shops in Southern California back in the 1970s and 80s.

According to Ngoy, he went to Westco for the supplies he needed for his shop, just like many doughnut business owners did back then. At the time, he was particularly looking for boxes that were cheaper than the standard white cardboard ones. Westco offered him the pink cardboard leftovers that “formed a 9-by-9-by-4-inch container with four semicircle flaps to fold together.” The size even perfectly held a dozen doughnuts.

While Westco is unable to verify who actually ordered the pink boxes first, Ngoy claims to be certain that it was either him or Ning Yen, his business partner.

“We doughnut makers were all about saving money,” Ngoy told the Times. “Why buy the more expensive white? Save a few pennies and make big bucks.”

As for Yen’s son, he thinks that it was more likely his father who first ordered the pink boxes. According to him, his dad may have at first been looking for a red box since refugees consider it as a lucky color but just ended up settling for the pink one.

What began as a cost-saving measure of Asian immigrants has grown into a tradition that many companies, even in other states now, use as a standard.

From small doughnut shops in Arizona and Texas to more established brands like Portland’s Voodoo Doughnut and Minneapolis’s Glam Doll Donuts, the pink box has become the go-to doughnut container.