Ukraine ? Authorities have checked 16,000 people for symptoms of chemical poisoning following a train derailment that ignited tankers loaded with yellow phosphorous in western Ukraine, the health minister said Friday.

Doctors examined thousands of emergency workers and residents in the Lviv region, where the fire belched clouds of toxic gas, said the minister, Yuriy Haydayev. More than 180 people remained hospitalized Friday, including 34 children.

Not everyone hospitalized had serious symptoms, Haydayev said.

“We hospitalized all children who feel discomfort in their eyes or throats, at their parents’ insistence, but this does not mean they were poisoned,” he said.

No deaths were reported.

The accident occurred Monday when a freight train derailed outside Lviv, near the Polish border, overturning 15 of 58 cars.

Six tanker cars containing yellow phosphorus caught fire, sending noxious fumes over 35 square miles.