Scientists have found a way to produce human blood, potentially on an industrial scale — thanks to a certain University of Edinburgh professor, Marc Turner, and his program’s funds from the Wellcome Trust.

With this new method, scientists hope they’ll produce a sort of “limitless” supply of type-O red blood cells, free of diseases and able to be transfused into any patient. Blood transfusions are used to replace lost blood after an injury or surgery. According to the National Institutes of Health, every year five million Americans require blood transfusions.

Through the use of pluripotent stem cells — regular cells removed from the human body and then transformed into stem cells — Turner and his team of researchers were able to create blood type O red blood cells. The technique will be tested in live humans for the first time, in a trial running through 2016 or 2017. In the experiments, researchers will test the artificial blood on people who have thalassaemia, a blood disorder that requires several transfusions.

“Although similar research has been conducted elsewhere, this is the first time anybody has manufactured blood to the appropriate quality and safety standards for transfusion into a human being,” Turner told The Telegraph.

There are eight different blood types but four major ones, according to the American Red Cross. Blood types are defined by the presence of certain antigens. Since antigens foreign to the body can trigger immune reactions, it’s important that people who receive blood transfusions are matched with donors who have the same blood type as them.

The four major blood types include Group A, Group B, Group AB, and Group O — the latter which has both A and B antibodies in the plasma, but no A or B antigens on the red blood cells. Donors with type-O blood cells can offer their blood to any of the others, but people with type-A can only donate to type-A or type-AB, and so on. Blood types are also defined by a “negative” or “positive” symbol, which is determined by the Rh factor, a third antigen. About 40 percent of the population has type O, making it the most common blood type.

Blood transfusions were often dangerous in the past due to the spread of diseases like hepatitis B or HIV, though today blood banks screen all donated blood for diseases. “Although blood banks are well-stocked in the U.K. and transfusion has largely been safe since the Hepatitis B and HIV infections of the 1970s and 1980s, many parts of the world still have problems with transfusing blood,” Turner told The Telegraph.

Last year, scientists from a Transylvanian university were able to create fake blood as well, and tested it successfully on mice. However, professor Radu Silaghi-Dumitrescu and his team from the Babes-Bolyai University in Cluj-Napoca, Romania, did not have the resources or funding to test it in humans. “Tests on humans are a very delicate topic, we need some very serious licenses and they represent an enormous risk,” Silaghi-Dumitrescu said.

Likewise, blood substitutes made from stem cells, like Turner’s project, have been experimented with before. Robert Lanza, chief scientific officer at Advanced Cell Technology, for example, has tried to make a very large supply of type-O blood; in 2008 the company reported it had created 10 billion red blood cells from human embryonic stem cells, though trillions of cells are needed for a blood transfusion. “The goal here isn’t to put the Red Cross out of business,” Lanza told Popular Mechanics. “Donated blood is always the first line of defense. But with this technology, you would have a safety net.” And whether it’s Lanza, Turner, or someone else, perhaps it’s just a matter of time before researchers are able to successfully transfuse this fake blood into humans.