Prior to the introduction of the Global Industry Classification Standard (GICSÂ®) in 1999, Standard & Poorâs used a classification system with 11 sectors and 115 industries, similar to the Standard Industry Classification (SIC), which was introduced in 1937.
Symptoms: Mood-change, lethargy,irritability,confusion,fatigue and memory problems and myself chest pain this past 5 months, could the gas be the problem? Doctor : Thank you for your question. Natural gas or propane inhalation for extended periods of time can lead to headaches, nause a, shortness of breath, dizziness, and altered mental status. It is quite likely that this exposure could be eliciting your symptoms.
The initial symptoms of CO poisoning can be mistaken for flu symptoms. 1  Symptoms occur or get worse shortly after turning on a fuel-burning device (e.g., generator, vehicle, tool).  More than one person in the home becomes sick at the same time (it usually takes several days for the flu to pass from person to person).