The Nuclear Regulatory Commission has scheduled an evening meeting Feb. 1 at the Ala Moana Hotel on its environmental assessment of Pa'ina Hawai'i LLC's proposal to build a cobalt 60 irradiation plant near Honolulu Airport.

The assessment concludes that there would be no significant environmental impact of building the plant, but project opponents who fought for the environmental review say it ignores some risks and inadequately assesses others.

Pa'ina proposes a facility in space leased from the state at the end of Lagoon Drive near the reef runway, where a radioactive cobalt source would be installed in an 18-foot-deep pool of water. Products such as fruit, cosmetics and medical supplies would be immersed in the pool, where the radiation would kill fruit fly larvae and disease-causing organisms.

Cobalt 60 is used in a number of processes besides food irradiation, including laboratory and industrial applications and sterilization of medical gear. The compound is also used in a variety of nuclear bombs.

The environmental assessment concludes that there is a minuscule risk that the radioactive material, which would be encased in steel containers, could be ruptured by events such as a tsunami, earthquake or even an aircraft crash. And in the case of an aircraft crash, it calculates the probability of a crash into the facility as one accident in 5,000 years.

"Based on the best-available information, the potential is negligible for natural phenomena or an aircraft crash to result in a loss of control of radioactive material to an extent sufficient to have an adverse impact on public health and safety," says a technical report attached to the environmental assessment.

Earthjustice attorney David Henkin, who represented Concerned Citizens of Honolulu in seeking the environmental study, said the assertions worry him.

"It strains credibility to suggest that a airplane fully loaded with fuel slamming into this thing would cause no possible radiation leaks," he said.

He also challenged the Nuclear Regulatory Commission's decision not to even consider the potential of terrorism.

"I think there is no question that it would be a potential target of terrorists," he said of the facility, which would be licensed to contain up to 1 million curies of cobalt 60.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.