RICHLAND, Wash. — Three workers at the Hanford Nuclear Reservation in Washington state received medical evaluations as a precaution after reporting suspicious odors and experiencing symptoms outside a radioactive waste tank farm.

The Tri-City Herald reports ( http://bit.ly/2spwuu7 ) that five additional workers also reported odors Tuesday but declined medical evaluations. They had no symptoms consistent with possible exposure to chemical vapors associated with waste held in underground tanks, according to the private contractor that operates the tank farms for the U.S. Department of Energy. Such symptoms have included coughing and headaches.

Hanford officials say no work that would’ve disturbed waste was being done in the vicinity.

Dozens of Hanford workers have sought medical examinations for possible exposure to chemical vapors since 2016. Some reported smelling suspicious odors and some experienced respiratory problems. Nearly all were cleared to return to work.