Or it could be a natural muck that got stirred up combined with summer temperatures and the lack of oxygen. My friend, it is part of the nature's works as it has nothing do with us at all.
You must be right, it must happen every summer. Too bad I never heard of this happening when I lived in Michigan. Because you and I both know that its supposed to get hot enough up in Michigan to deprive the perfectly clean fresh water of lake Erie of oxygen.
Add that along with a natural occurrence of lake muck and scum build up and you've got what they must love to clean up almost yearly.
I'm not arguing that this wasn't something that a chain of events in nature caused to happen, just saying we didn't help, as a matter of fact I'm saying that we are partly responsible.
Like I stated originally, lake Erie has caught on fire from the pollution that it contains, you can't say that that is natural. Even though lightning striking the lake is what caught it to catch on fire. Lighting is natural but it isn't what caused it to catch on fire, the fire itself was caused solely by our impact (pollution).