Even so, threads remain, some hidden, some exposed but too twisted and interlaced to fully recognize or remove safely.

Bee experts had told them the hive was too delicate to remove safely and numerous pest controllers had simply refused the job because it was too dangerous.

The surgeons warned that even small devices could be difficult to remove safely.

The asbestos cost the company millions to remove safely and there were more costs when concrete support pillars began cracking and had to be reinforced.

Once the fuel has been irradiated, the fission products mixed with the fissile materials are highly radioactive and require special handling to remove safely, another non-proliferation feature.