Spell Check Macro Issue - Runtime Error 13 when over 250 characters in cell.

I'm relatively new to VBA, and I'm using a spell check macro to check spelling in each cell of a sheet. I've found that if there are over 250 characters in a cell, it causes the macro to crash and displays the Runtime error 13 message. I'm in the sign design and manufacturing business, and each cell contains the text on a component of a sign, so it can't be split into other cells. Here's my code:

Sub Spell_Check()
For Each cl In ActiveSheet.UsedRange
If Not Application.CheckSpelling(Word:=cl.Text) Then _
cl.Interior.ColorIndex = 43
Next cl
End Sub

Anybody know of a way to bypass this 250 character limit? I use Excel 2010.