RICHLAND — Workers cleaning up the Hanford nuclear reservation are going after radioactive wasp nests.

The Tri-City Herald reports 6 to 12 inches of top soil are being dug up this month from 6 acres near the H Reactor. And, workers will dig up more individual mud dauber wasp nests over about 75 acres of the nuclear reservation in southeast Washington.

The contractor handling the clean-up, Washington Closure, says the nests were all built in 2003 when water was used to dampen dust during demolition of an H Reactor basin. That attracted the wasps that used the mud to make tube-shaped nests for eggs.

Spokesman Todd Nelson says the nests are “fairly highly contaminated.”