"It took five days but they got 'er done," according to Atmos spokesperson Shawn Michie. No more gas will vent into the atmosphere because the relief valves have been replaced with regulators. Previously, whenever there was a malfunction from overpressurization, gas would simply vent into our airshed. Atmos made this upgrade after receiving numerous complaints from neighbors about loud venting noises which woke them up in the middle of the night.
These new regulators are designed to reduce pressure rather than allowing gas to spew into our community. We feel relieved about this since ~ when the breeze is blowing in just the right direction ~ we smell mercaptan on our property a half mile away. In addition, we have two public schools near these two metering stations.
We were under the impression that this was one gas metering station, but we learned that this southeast Arlington Gas Metering Station is actually two. (See photo above.) The one on the left serves the City of Grand Prairie, Texas and the one on the right serves the City of Arlington, Texas. We are always discovering new things in Gasland!
Now let's talk about mercaptan. We are told that mercaptan is added to natural gas for safety reasons since natural gas is odorless and explosive. [We certainly wouldn't want a repeat of the New London School explosion.] What we are not told about mercaptan, however, is that it is a toxic, hazardous chemical. Short term exposure can cause headache, dizziness, nausea, pulmonary irritation, wheezing, rapid heart beat, and irritation of the eyes and mucous membranes. In lab experiments monkeys, rats, and mice that inhaled mercaptan exhibited altered blood chemistries and cellular changes of the liver, lungs, and kidneys.
According to the ATSDR (Agency for Toxic Substances and Disease Registry):
We have very little information on the health effects of exposure to methyl mercaptan. A worker exposed to very high levels (exact amount unknown) of this compound for several days when he opened and emptied tanks of methyl mercaptan went into a coma (became unconscious), developed anemia (a blood disorder) and internal bleeding. He died within a month after this incident.
We do not know whether long-term exposure of humans to low levels of methyl mercaptan can result in harmful health effects such as cancer, birth defects, or problems with reproduction.
Methyl mercaptan can be smelled and recognized in Air when it is there at a level of about 1.6 ppb (1.6 parts of methyl mercaptan per billion parts of air). It can be smelled when it is present in water at a level far lower than 1 ppb.
Rest assured that Atmos employees may monitor these stations through their I-Phones 24/7, 365 days/year. Pressure may also be controlled remotely out of the Pressure Control Office located in Lincoln Center in Dallas.
Regarding health-effects of long-term exposure to low levels of mercaptan: