Called the agent and the agent said "WOW, this is bad, we can't sell a house with toxic black mold." 

Some other Cities and States might have lax laws but id not want to live on Toxic waste nor be responsible for renting to someone else to live there.

I wrote the ad right after getting my 1 days notice, so I was a little irritated and it came out in my writing.

Apparently the night before the city government had decided to list the entire neighborhood with the Federal Superfund list for toxic clean-up.

As part of normal human breathing, we exhale CO2 (CO2 is toxic in cases where the concentration is abnormal).Even though you have those detectors installed, you still have to make certain that the heating systems are properly installed and operating properly.

Anything unnatural is toxic to the body so beware.

Be aware that decades ago heavy industry put a lot of arsenic in the air, and toxic levels are still present in the ground in some north end areas.

This minimizes the inconvenience of the existing tenant (no need to irritate them even if they are moving out), saves you time, and puts a little pressure on the prospective tenants to submit an application since others are there at the same time.  

Not all mold is toxic mold.

I am so irritated at this.