Natural gas processing plants would be required to report chemical discharges on U.S. EPA’s Toxics Release Inventory under a U.S. EPA proposal set for publication tomorrow in the Federal Register.

The proposed rule would add to the inventory about 282 facilities that recover liquid hydrocarbons from oil and gas field gases.

“Adding these facilities would meaningfully increase the information available to the public on releases and other waste management of listed chemicals from the natural gas processing sector,” the proposal says.

Among chemicals used by such facilities [And what about the mystery frac chemicals?]:

The recommended limit of 10 ppm does not guarantee worker safety. If should not be used as a guideline demarcating safe and dangerous concentrations of hydrogen sulfide. Because of wide variations in individual susceptibility some workers may experience problems at concentrations at or below the threshold limit.

The safest exposure to Hydrogen sulfide is no exposure at all.

Effects of exposure

Hydrogen sulfide at low levels has a distinctive rotten-egg odour and workers mistakenly assume that the absence of smell means that they are not exposed to it. Smell is a poor warning sign of hydrogen sulfide.

At higher concentrations a sweet smell may be noted, but at even greater concentrations, hydrogen sulfide can “paralyze” the sense of smell and the ability to smell is lost. Some workers are congenitally (by birth) unable to smell hydrogen sulfide. That is why the air should always be monitored by instruments designed to detect hydrogen sulfide.