Some of the largest air emissions in the oil and gas industry occur as natural gas wells that have been fractured are prepared for production.

During a stage of well completion known as "flowback," fracturing fluids, water and reservoir gas come to the surface at a high velocity and volume. This mixture includes a high volume of VOCs (volatile organic compounds) and methane, along with toxins such as benzene, ethybenzene and n-hexane. The typical flowback process lasts from three to 10 days.

Hydrocarbons are naturally occurring organic compounds that can occur as gases, liquids or solids. The most common hydrocarbons are natural gas, oil and coal.

VOCs are hydrocarbon compounds that are generally highly toxic, often carcinogenic, and easily absorbed into water (some examples are propane, benzene, toluene, ethylbenzene and xylene.)

Since VOCs, both manmade and naturally-occurring are frequently used in drilling operations, there is a great deal of concern about the potential for ground and drinking water contamination resulting from their use.

Life and sickness in the gas patch

"We were very against it," Dee Hoffmeister from Dry Hollow, Colorado recalled. They watched a neighbor deal with another gas drilling company and ultimately move away to escape the smells, noise and other problems.

Ultimately, Hoffmeister was convinced that they had no choice but to lease their rights . D rilling started six years ago. H er grandson was diagnosed with asthma short ly afterward and Hoffmeister has suffered from recurring illness with no diagnosis.

T he worst was a big gray cloud enveloping their house. " I suppose it was all the trucks idling ," Hoffmeister said . Whatever the source, when she entered the house she started getting dizzy and passed out .

Her family drove her to her daughter's house in West Glenwood, where she stayed for eight months. Any time she back to Dry Hollow, she'd fall ill immediately, feeling dizzy, light-headed and weak, with occasional stomach upset.

In 2011, a workover rig was unexpectedly erected near her home. P owerful fumes drifted from the rig to her home , enveloping her, her daughter and grandson.

" The first morning the smells hit, they just started gasping for air," Hoffmeister recalled. They shut down the air conditioning to keep the smells out, but that had little effect.

Nowadays, Hoffmeister's pains tend to migrate from one part of her body to another, and her hands and feet itch and burn much of the time. She continues to spend a lot of time inside, unable to water or work in her garden when the odors become unbearable. Her grandson continues to suffer asthma attacks if the fumes become intense.

Dee Hoffmeister is just one of the many suffering from the gases produced by oil and gas drilling. The industry has long discounted claims by those living near gas wells that the drilling-related activities were making them sick.

Hydrogen sulfide gas

H ydrogen sulfide gas (H2S) develops naturally in conjunction with crude oil and natural gas . It's produced when certain bacteria consume sulfur-bearing organic matter. Whether there's H2S depends mainly upon the environment when the rock formations were deposited.

When there's hydrogen sulfide in natural gas formations, it's called "sour." If there's no hydrogen sulfide, it's called "sweet."

T here are areas in Colorado, like the Western Slope, where the gas is "sour" and contains a significant amount of H2S. In low concentrations it smells like rotten eggs. There may be less hydrogen sulfide on the Front Range in theNiobrara formation.

Hydrogen sulfide a significant safety issue

According to the U.S. Centers for Disease Control, hydrogen sulfide is a hazardous and toxic gas that, when inhaled, can cause severe respiratory distress, headaches, loss of motor control and memory and other human malfunctions.

C oncentrations lower than 10 parts per million (ppm) are considered relatively harmless. At 100 ppm or more, it can paralyze the olfactory nerve and cause a loss of the sense of smell. Exposure at increasing concentrations can cause nausea and vomiting, difficulty breathing, shock, convulsions and death in the most severe cases.

Hydrogen sulfide detectors and warning horns on the drilling rig warn of danger. F lags or windsocks show the drilling crew how to get out of the way.

"Deaths due to breathing in large amounts of hydrogen sulfide have been reported in a variety of different work settings, including ... oil and gas well drilling sites," stated the CDC's Agency for Toxic Substances and Disease Registry. One whiff of a strong concentration can be fatal.

In September 2011, a COGCC commissioner sa id he is concerned the agency overlooked reports that a toxic gas was being encountered at near-fatal levels on Western Slope drilling sites. In a presentation in November 2011, Stuart Ellsworth, engineering manager for COGCC , said hydrogen sulfide gas has been reported at 312 of Noble's 353 producing wells in the area.

In most instances, the gas was at concentrations lower than 10 parts per million (ppm). But in four incidents, Ellsworth reported, Noble encountered hydrogen sulfide gas at concentrations of 100, 170, 200 and 450 ppm. Exposure at those levels can cause loss of the sense of smell, breathing difficulties, eye irritation and, at around 500-700 ppm, death.

In December 2011, Noble Energy report ed dangerous levels of hydrogen sulfide gas have been measured at least once at dozens of its wells not just in Garfield County, but Weld County as well. The company says 21 of its wells in the Piceance Basin have had levels at or above 100 parts per million on at least one occasion, as have 32 wells in the Grover oil and gas field in Weld County.

Type: CHEMICAL HAZARD Date: 04/03/2009
Complainant: Shawn Jacobson 510 High Flume Durango CO 81303
Description of Complaint: Complainant & wife returned home about 6-7:30 p.m. and noted the compressor at this location was louder than normal. They drove to the well pad to check and see what was happening and to obtain the operator phone number from the sign. Both got dizzy and disoriented while on the pad and Mr. Jacobson stated he was throwing up by the time they got back to the house. The complainant called the Operator and was put in contact w/ Walt Schneider-Williams Field Lead. Mr. Schneider said he would send someone out to shut off the well and would call Mr. Jacobson back. Mr. Jacobson has not yet received a call back and wants to know if he and his wife need to seek medical care. He indicated that both had headaches all night and experienced a metallic taste. Mr. Jacobson saw a pumper at the wellhead this morning, but the well was still in production. Mike Meschke of San Juan Basin Health was also called and a message left for him. SW EPS indicated she would contact staff at Williams and request them to communicate needed information with the Jacobsons.
COGCC Response: Matter was referred to Williams Production Company for followup with the complainant. No further action at this time.


New EPA air quality rules for fracking get hearing inĀ Denver

What are Fracking and Split Estate?

Life and sickness in the gas patch

Colorado Officials Investigating Hydrogen Sulfide Reports At Oil And Gas Drilling Sites

Colorado state officials looking into hydrogen sulfide reports

Fatalities in the energy fields: 2000-2006

State officials looking into hydrogen sulfide reports

COGCC commissioner voices concerns' about H2S

Hydrogen sulfide high at 53 wells, Noble says


Fracking basics
what is fracking?
spread of fracking in Colorado
history of fracking
documentaries & videos

What goes wrong


faulty cementing
releases of gas
methane in water
fractures reaching aquifers
unknown causes

How fracking is harmful
air quality
Ultra Resources violations
water quality
lack of water in Colorado
food supply & livestock
health effects
explosions & fires

property values
quality of life

tourism & local economy
toxic waste
increased crime rates

What can be done?
proposed laws
Coloradans need an advocate
rewriting regulations
overcoming preemption
how to comment on a permit
less-toxic fracking
other energy sources

Take action now
meeting schedule
sample letters
addresses for letters

politicians' comments

Colorado Springs
& El Paso County
organizations & websites
history of drilling in El Paso County

organizations & websites

organizations & websites

About us
our mission
sign up for the latest news