Intended for healthcare professionals


Women and children suffer most from exposure to coal smoke

BMJ 2006; 333 doi: (Published 07 December 2006) Cite this as: BMJ 2006;333:1192

Domestic coal combustion in unvented stoves exposes users to mercury, arsenic and fluorine toxicity, while males also obtain their share of a potential carcinogen by consuming deep fried foods.

Anne Glusker writes regarding a report from the International Agency
for Research of Cancer citing a paper showing the carcinogenic potential
of burning coal and biomass fuels in poorly ventilated areas (1). The
agency further cites the paper that points also to the observation that
frying at high temperature (including stir frying, deep frying, and pan
frying) also increases the risk of lung cancer, regardless of the kind of
cooking oil that was used for the process.

We like to add further to this article regarding the importance of
burning these fuels in well ventilated areas. The burning of coal has been
shown to be a major cause for the release of mercury into the air (2,3),
accounting for about 38% of the total mercury emission in China (based on
data of 1999) (4). Mercury in all forms has been shown to be toxic (5).
Exposure to mercury, today, is mainly dietary or occupationally dependent
even though many get their mercury from their amalgam fillings (5). Its
neurotoxicity has been noted for a long time and recently its role in
cardiovascular diseases has raised concern on account of its role in
propagation of oxidative stress (3). Highly significant levels of mercury
has been detected in breast cancer tissue samples compared to controls in
one study (6). Until procedures to remove mercury from coal, using
biological treatment for example (7), are perfected the dangers of using
coal as fuel will continue. At least, proper ventilation will help the
immediate user to escape from the toxicity of mercury and other
potentially hazardous air pollutants (HAPs) in addition to toxicity of
other carcinogens.

The United States EPA (Environmental Protection Agency) issued a
report to Congress in 1998 regarding the health impacts of 189 potentially
HAPs emitted from coal-burning electric utility generators (8). The EPA
concluded in this report that, with the exception of mercury, there was no
compelling evidence to show that trace element emissions cause health
problems to humans. This is, in part, a result of the fact that the coals
burned in the U.S. generally have low to modest concentrations of HAP
elements and that many coal-burning utilities use pollution control
systems that are sophisticated and efficiently reduce the emissions of
HAPs (8).

However, domestic coal combustion has had serious ill effects on the
health of millions of people worldwide. Several hundred million people
commonly burn raw coal, in China alone, in unvented stoves that fill their
homes with high levels of toxic metals and organic compounds. A mercury
concentration of 55 ppm (about 200 times the average mercury concentration
in U.S. coals) was found by chemical analysis of a coal sample being used
in Guizhou Province, China. Severe arsenic poisoning is a serious
byproduct of this process, in the Guizhou Province in southwest China. The
main source of the arsenic appears to be consumption of chili peppers
dried over fires fueled with high-arsenic coal. Up to 35,000 ppm arsenic
were found in the coal samples from this region. Chili peppers dried over
high-arsenic coal fires were shown to adsorb 500 ppm arsenic on average.
Such combustion of coal has also shown to cause selenium poisoning and
possibly mercury poisoning. The health problems caused by fluorine
volatilized during domestic coal use are far more extensive than those
caused by arsenic. More than 10 million people in Guizhou Province and
surrounding areas suffer from various forms of fluorosis, and it also has
been reported from 13 other provinces, autonomous regions, and
municipalities in China (8).

As the author points out, women and children suffer the most owing to
the fact that they are the ones at home most of the time. However, there
is another aspect in which the males as well as the women and children who
will be victims of a carcinogenic diet. It has been pointed out that
frying at high temperature (including stir frying, deep frying, and pan
frying) also increases the risk of lung cancer (1). However, foods that
have been deep fried, roasted, or baked at temperatures over 120 ¢ªC
result in the formation of high levels of acrylamide which is a potent
neurotoxin and carcinogen as well as being implicated in genotoxicity and
reproductive toxicity (9). These foods are consumed by men as well as
women. Thus, ultimately no one is spared from exposure to this kind of
possible carcinogens.


1. Glusker A. BMJ 2006;333:1192.

2. Lipfert F, Morris S, Sullivan T, Moskowitz P, Renninger S.
Methylmercury, fish consumption, and the precautionary principle. J Air
Waste Manag Assoc. 2005; 55:388-98.

3. Virtanen JK, Rissanen TH, Voutilainen S, Tuomainen TP. Mercury as
a risk factor for cardiovascular diseases. J Nutr Biochem. 2006 Jun 15;
[Epub ahead of print]

4. Zhang L, Wong MH. Environmental mercury contamination in China:
Sources and impacts. Environ Int. 2006, Aug 14; [Epub ahead of print].

5. Hylander LD, Goodsite ME. Environmental costs of mercury
pollution. Sci Total Environ. 2006;368:352-70.

6. Ionescu JG, Novotny J, Stejskal VD, Latsch A, Blaurock-Busch E,
Eisenmann-Klein M. Increased levels of transition metals in breast cancer
Neuro Endocrinol Lett. 2006 Aug 5;27(Suppl1) [Epub ahead of print].

7. Klasson KT, Borole AP, McKeown CK, Hamilton CY.Biomodification of
coal to remove mercury. Appl Biochem Biotechnol. 2006;129-132:897-908.

8. Finkelman RB, Belkin HE, Zheng B. Health impacts of domestic coal
use in China. Proc Natl Acad Sci, USA, 1999;96:3427-31

9. Carere A. Genotoxicity and carcinogenicity of acrylamide: a
critical review.
Ann Ist Super Sanita. 2006;42:144-55.

Competing interests:
None declared

Competing interests: No competing interests

13 December 2006
Biji T. Kurien
Senior Research Scientist
Jobin T. Kurien, Mustang High School, Mustang, OK 73064, USA
Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA