"baleful effect" is correct and usable in written English
You can use it to describe a bad or harmful result or influence. For example: The industrial revolution had a baleful effect on the environment.
You "strongly oppose" a candidate because you believe he'd have a baleful effect on our lives.
The gay-marriage controversy has had a baleful effect on current men's fashion.
That the hospital searches everyone mitigates this baleful effect slightly, because no employee is being singled out for special scrutiny.
But this time the scare is about more than bad mortgage loans and their baleful effect on the credit markets.
This craggy geography might well be regarded as the devil's work: for centuries it had a baleful effect on the region's history.
It gives little away to write that a difficult heroism emerges: one with older, deeper roots than the heroics that have bloomed on both sides over the generations to such baleful effect.
This has had baleful effects in many parts of the world.
But 200 years later, the last baleful effects of that revolution and the reaction against it have faded.
But because we've so long let cars dominate city life, we take them, and their baleful effects, for granted.
Mary Ezekiel, staff nurse at University College London Hospital, itemized the baleful effects that pension cuts — the cause of the day's action — will have.
(The AMT has repeatedly been "patched" to lessen its baleful effects, and surely will be again).But the real problem is that the first baby-boomers retired last year.
