Sewage blockages happen everywhere, and septic tanks need emptying regularly. When people are selling their homes they often skimp on the maintenance side of things and problems mount up.
If you have a blocked drain, or suspect septic tank problems, you need to be wary of opening drain covers, because of the possible build up of toxic gases. This is especially so if you are moving into a property that has been vacant for some time. If there are depressions in the ground near your septic tank, stay well away from the area until a professional survey has been carried out. Find more help on septic tanks at http://www.septic-tank-services.info
Most people will recognize hydrogen sulfide as one of the gases given off by stink bombs.
Did you know that hydrogen sulfide gas is more poisonous than hydrogen cyanide? Luckily you can smell it long before it reaches toxic concentrations. As the concentration increases, you lose the ability to smell the gas. This should be taken as a danger sign and a signal to move rapidly away from the area.
When sewage backs up due to a blockage, bacteria produce hydrogen sulfide gas and the concentration can build up to fatal levels underneath the manhole cover. If the gas is not immediately present there is still a danger. When someone pushes a drain rod through the pipe, it stirs up the sewage. This process causes Hydrogen sulfide to be released in high concentrations.
This gas can cause death by respiratory failure and victims often fall into the sewage. Rescuers who are not equipped with respirators are themselves at great risk and care needs to be taken if the incident is not going to be made worse.
