Groups Call for Action On Hydrogen Sulfide Gas

Nearly 130 public health and environmental organizations and community groups from across the nation are requesting that US EPA administrator Carol Browner formally list hydrogen sulfide as a hazardous air pollutant.

Hydrogen sulfide (H2S) is well known as an almost instantaneous killer at Higher concentrations, but the letter to the EPA administrator, dated January 25, 1999, and co-signed by more than 130 groups and individuals including the national Sierra Club, the American Lung Association of Michigan, Communities for a Better Environment, the National Oil Refinery Network and dozens of community groups in thirty-two states, argues that "poison gas" or "rotten egg gas" is a dangerous toxic release even at remarkably low level, sublethal concentrations in low part per billion ranges.

The groups signing the letter would like to see H2S added to the list of 188 chemicals (the so-called HAPs) regulated by the EPA under Title III of the 1900 Clean Air Act Amendments. They claim that newer medical research demonstrates serious and permanent central nervous system damage at the chronic low levels to which many oil refining and livestock feeding communities across the nation are exposed. Listing the chemical would protect public health, and in particular the health of children and minorities, they say. Communities of color are disproportionately represented in situations where hydrogen sulfide is an emissions hazard.

"Common sources of H2S," according to Ronald J. Parry, Ph.D., Rice University professor of Chemistry, "are petroleum refineries which use sour crude oil, large hog farms and confined animal feeding operations called CAFOs, paper and pulp mills, oil and gas operations, sewage treatment plants, and dozens more among approximately seventy-three types of sources." (See longer list at end) "This makes H2S one of the most common toxic air pollutants in many communities throughout the nation," Parry added.

"Public health scientists now recognize that hydrogen sulfide is a potent neurotoxin, and that chronic exposure to even low ambient levels causes irreversible damage to the brain and central nervous system," stated Neil Carman, Ph.D., who is clean air director for the Lone Star Chapter of the Sierra Club, a consultant to the Galveston-Houston Association for Smog Prevention, and a former Texas state environmental official.  "Children are among the most susceptible to this poison gas. It is unacceptable for communities to have to continue suffering the ill effects of H2S when the technology to control H2S emissions is available and affordable," Carman stressed.

Demonstrable symptoms of chronic exposure, found by researchers, include pronounced deficits in balance and reaction time, as well as such ailments as dizziness, insomnia, and overpowering fatigue.  According to the several studies of the medical researchers cited in the letter to EPA, in chronic, low level exposures, one may observe abnormal neurobehavioral functioning and altered mood states (e.g., depression, fatigue, tension, vigor). In addition, numerous CNS-brain effects occur including: changes in brain density, headache, memory loss, reduced sense of smell, loss of balance, dizziness, sleep difficulties, and fatigue. Numerous cases reported in the literature support the CNS toxicity of H2S. Many of the effects are persistent.


US EPA - the Report to Congress on Hydrogen Sulfide Air Emissions Associated with the Extraction of Oil and Natural Gas (EPA Report to Congress), issued in October 1993 by the EPA Office of Air Quality Planning and Standards (EPA-453/R-93-045)

Kilburn, Kaye H: 1997, Panel on Hydrogen Sulfide, American Public HealthAssociation's annual meetings, November 11, 1997, Indianapolis, IN.

Kilburn, Kaye H,:1993, Am J Med Sci 306:301-5.

Kilburn, Kaye H, and RH Warshaw: 1995, Tox Ind Health 11:185-96.

Legator, Marvin S, and Chantele Singleton: 1997: Panel on Hydrogen Sulfide,American Public Health Association's annual meetings, November 11, 1997, Indianapolis,IN.

Borda, Bob: 1997, Panel on Hydrogen Sulfide, American Public Health Association's annual meetings, November 11, 1997, Indianapolis, IN.

Morris, Jim: New alarm over hydrogen sulfide—Researchers document lasting damage to human nervous system. A three-part investigative report, Houston Chronicle, November 1997. See Houston Chronicle web site.


Dr. Marvin Legator, University of Texas Medical Branch at Galveston, Texas.Department of Environmental Toxicology. (409) 772-1803

Dr. Kaye Kilburn, University of Southern California Medical School, Los Angeles, CA.


1) crude oil petroleum refineries (primarily sour crude oil); 2) pulp and papermills; 3) paper production; 4) municipal sewage treatment plants; 5) large hog farms-livestock operations (CAFOs); 6) sour natural gas processing plants; 7) sour crude oil/sour natural gas handling stations/bulk petroleum terminals; 8) oil and gas production; 9) oil/gas transmission plants; 10) bulk storage and pipelines; 11) Portland cement kilns; 12) municipal waste landfills; 13) coke ovens; 14) coal gasification plants; 15) tanneries; 16) slaughterhouses and rendering plants; 17) geothermal power plants; 18) sulfur products and hydrogen sulfide production; 19) animal fat and oil processing; 20) asphalt storage facilities; 21) blast furnaces, breweries and fermentation processes; 22) fertilizer production; 23) glue making; 24) metal processing (gold ore, lead ore, lead removal, copper ore sulfidizing and metallurgy); 25) barium carbonate and barium salt production; 26) - 46) miscellaneous manufacturing processes including the manufacture of carbon disulfide, dyemaking, textile printing, thiophene production, sulfur production, soap production, phosphate purification, hydrochloric acid purification, cellophane production, rubber and plastics processing, soap making, silk making, rayon making, pyrite burning, photoengraving, synthetic fibers, polysulfide caulking production, bromide-bromine, artificial flavor making, and refrigerant making; and 47) -50) fish,sugar beet and sugar cane processing, as well as other miscellaneous sources.