A chemicals factory has exploded outside Cairo's main airport injuring 12 people with an army spokesman saying the blast was brought on by high temperatures.
Egyptian firefighters have worked to bring the fire under control after a petrochemical storage facility exploded in the capital city's north on Thursday night.
State news agency MENA says 12 people have been taken to hospital with injuries, quoting a security source.
The minister of civil aviation, Younis al-Masri, said air traffic at the airport was unaffected by the explosion, which could be heard across the area.
"Due to high temperatures, an explosion happened at a petrochemicals storage belonging to the Heliopolis for Chemical Industries," said Colonel Tamer al-Rifai, the military spokesman, in a social media posting.
"Civil defence trucks were deployed to bring the fire under control," he added.
Rifai did not say who owned the factory, but security sources and some internet postings suggested it belonged to the armed forces.
Witnesses said ambulances and fire trucks rushed to the scene as a cloud of black smoke rose over the area.
State television said firefighters had managed to bring the fire under control.
Egypt is battling an Islamist militant insurgency that has carried out attacks, mainly in the remote Sinai Peninsula, where the army has been conducting a security operation since February.
Violence appeared to have subsided in recent months, with no incidents reported in the country's mainland outside Sinai.