I am having trouble getting a macro to "fire" when a cell change is made.
The cell is a formula, and the formula is based on a cell that "refreshes"
every 30 minutes from a web query. When the cell hits a certain value it
should send an email to several workers, but this does not occur.

Any thoughts/suggestions?

here is the code:

Private Sub Worksheet_Change(ByVal Target As Range)
Dim rng As Range
If Target.Cells.Count 1 Then Exit Sub
On Error GoTo EndMacro
If Not Target.HasFormula Then
Set rng = Target.Dependents
If Not Intersect(Range("C11"), rng) Is Nothing Then
If Range("C11").Value < 0 Then MYMACRO
End If
End If
EndMacro:
End Sub