The main air traffic control tower at Washington Dulles International Airport was evacuated just after 10 a.m. this morning after fumes from a nearby construction site made some people working in the tower feel ill. The WaPo reports that two controllers and one supervisor were transported to a hospital, but their shifts were quickly filled by back-up staff and the evacuation caused no significant delays — an average of just about 27 minutes for delays at Dulles was reported. NBC4 is calling the fumes “smoke” and describes the construction site as being part of the new airport’s main terminal train system.

If you have a flight out of Dulles this afternoon, WTOP says that airport officials are still evaluating what to do about flights between noon and 2 p.m., and are encouraging travelers to check with their airlines for updates. In other words, despite the airport doing a decent job of keeping things going on time today, travelers could be in for some problems this afternoon. Good luck!