In Drilling Down,
we wrote about Elizabeth Chandler, a veterinarian in western Colorado.
Dr. Chandler has been observing health changes in livestock, including
goats, pigs and cattle, that are kept near natural gas production
activities. She is particularly concerned about reproductive changes,
including unexplained, dramatic increases in birth defects,
stillbirths, and reduced fertility, where she has ruled out other
potential medical causes through testing. One hog farmer estimates his
losses at more than $50,000. We also wrote about Rick Roles, who
observed reproductive changes in his horses and goats, and ranchers in
New Mexico who have lost cattle that were exposed to oil and gas waste.
Other parts of the country are now reporting livestock impacts from
oil and gas production. Oil and gas chemicals are suspected as the
cause of the deaths last week of 16 cattle in Louisiana. A Pennsylvania farmer is concerned about the recent deaths of four cattle. A
farmer in Arkansas told me about her concerns that natural gas
production is the cause of death and other health effects in her cows.
Almost 25% of her cattle died when kept in a pasture where three wells
were drilled above the water source - a loss of over $35,000. She has
also observed stillbirths, birth defects, and drastic reductions in
milk production. Tests indicated lead, arsenic, barium and other heavy
metals that are above safe levels in their soil and water. A goat
farmer in Oklahoma who is located across the road from oil and gas
activities told me that her goats stopped producing milk; she sold them
all and her farm is now in foreclosure.
A 2000 study looked at possible associations between oil and gas
operations and cattle reproduction and mortality, and found an
increased risk of stillbirths linked to exposure to flaring of sour gas
(gas with high levels of hydrogen sulfide).
A 1991 study reviewed seven cases of suspected poisoning of livestock
related to oil and gas materials in Oklahoma, cases described as
routine in oil and gas producing areas of the state.
We should be concerned about all of these reports; we need more science
on this topic. Livestock incidents may be an indicator of contamination
of air and water that can impact humans as well as animals. In
addition, there may be risk to humans who eat or drink products from
 Waldner, C. L. et al.,
Associations between oil- and gas-well sites, processing facilities,
flaring, and beef cattle reproduction and calf mortality in western
Canada," Preventive Veterinary Medicine 50 (2001) 1-17.
 Edwards, W.C. and D.G.
Gregory, "Livestock Poisoning from Oil Field Drilling Fluids, Muds and
Additives," Veterinary and Human Toxicology 33 (5) October 1991,