“grow dangerous” is a correct and usable part of a sentence in written English.
You can use it to describe situations becoming more treacherous or risky. For example, "As the storm intensified, the waves on the lake began to grow dangerous."
The rift between Jewish and Arab Israelis, always wide, is growing dangerous.
Early each morning, before the sun grows dangerous, crowds of Iraqis gather at the Assassin's Gate.
For all its gorgeously eerie omens ("The red Seth squirmed unhappily in my palm, like a little dinosaur dreaming of amber," says Ava, as her own voyage grows dangerous) "Swamplandia!" stays rooted in the Bigtree family's emotional reality.
At the same time, the Egyptians have downgraded their relations with Israel; the Jordanians, with rioting in the streets to demand that the Israeli ambassador be sent packing, may do the same; and the Lebanese border has again grown dangerous.
Yet as day bleeds into night, which turns to morning on the grounds of Oliver's country home (lyrically designed by Scott Pask, with lighting to match by Brian MacDevitt), you sense a growing, dangerous attraction between these opposite types (well, duh).
He said that the ECB could very well buy up commercial paper if it felt banks weren't lending enough, as well as government bonds if it felt the risk of deflation was growing dangerous.
And the linkages between motherhood and alcohol are not just problematic in the short term, they're part of a growing, dangerous trend that is seeing spikes in women binge drinking and increases in early mortality.
Yet few events, even in distant places, have no impact on America, and many (not all) grow more dangerous if neglected.
Now scientists have created tiny particles in the laboratory that mimic those good carriers, scooping up the cholesterol before it can grow into dangerous deposits of plaque.
The prime minister will set out the case for RAF jets and drones to strike at targets in Syria, telling MPs that Isis must not be allowed a "safe haven" in which to grow more dangerous.
