Deliberate industrial production depends on neutron activation of bulk samples of the monoisotopic and mononuclidic cobalt isotope 59Co.

[5] Measurable quantities are also produced as a by-product of typical nuclear power plant operation and may be detected externally when leaks occur.

In the latter case (in the absence of added cobalt) the incidentally produced 60Co is largely the result of multiple stages of neutron activation of iron isotopes in the reactor's steel structures[6] via the creation of its 59Co precursor.

[7] The main advantage of 60Co is that it is a high-intensity gamma-ray emitter with a relatively long half-life, 5.27 years, compared to other gamma ray sources of similar intensity.

The physical properties of cobalt such as resistance to bulk oxidation and low solubility in water give some advantages in safety in the case of a containment breach over some other gamma sources such as caesium-137.

60Co does not occur naturally on Earth in significant amounts, so 60Co is synthesized by bombarding a 59Co target with a slow neutron source.

[11] In the United States, as of 2010, it is being produced in a boiling water reactor at Hope Creek Nuclear Generating Station.

The rest is taken up by tissues, mainly the liver, kidneys, and bones, where the prolonged exposure to gamma radiation can cause cancer.

These observations support the radiation hormesis model,[17] however other studies have found health impacts that confound the results.

[18] In May 2013, a batch of metal-studded belts sold by online retailer ASOS were confiscated and held in a US radioactive storage facility after testing positive for 60Co.

[19] A radioactive contamination incident occurred in 1984 in Ciudad Juárez, Chihuahua, Mexico, originating from a radiation therapy unit illegally purchased by a private medical company and subsequently dismantled for lack of personnel to operate it.

The radioactive material, 60Co, ended up in a junkyard, where it was sold to foundries that inadvertently smelted it with other metals and produced about 6,000 tons of contaminated rebar.

[20] In the Samut Prakan radiation accident in 2000, a disused radiotherapy head containing a 60Co source was stored at an unsecured location in Bangkok, Thailand and then accidentally sold to scrap collectors.

[21] In December 2013, a truck carrying a disused 111 TBq 60Co teletherapy source from a hospital in Tijuana to a radioactive waste storage center was hijacked at a gas station near Mexico City.

[23][24] Despite early reports with lurid headlines asserting that the thieves were "likely doomed",[25] the radiation sickness was mild enough that the suspects were quickly released to police custody,[26] and no one is known to have died from the incident.

[30] In the Wu experiment, researchers aligned 60Co nuclei by cooling the source to low temperatures in a magnetic field.