If the members of the four delimited categories are counted as separate chemicals, the TRI Program covers 690 chemicals and chemical categories (i.e., 595 + 27 + 68). Note: methyl mercaptan and 2,2-dibromo-3-nitrilopropionamide are under administrative stays and are not currently reportable.
1 Open all the doors and windows.  2 You want to make sure you ventilate the house, Altman said. 3  If you suddenly notice your grass or shrubs have changed color, looking more brown or rusty, that could be a sign of a leak: the gas pouring out of the pipes.
Symptoms of Natural Gas Exposure. Natural gas exposure can occur when appliances, heating systems and pipes in your home leak gas. Natural gas contains chemicals such as methane, ethane, propane, butane and carbon monoxide. The gas is odorless and colorless, which makes detecting a leak difficult.