Tuesday, August 5, 2008

Benzene and Radiation Risks Compared

Risks from low level radiation exposures appear to be low at worst, and the risks may be confined to older workers. Research on Hanford workers hired between 1944 and 1978 found that only workers who were exposed after the age of 55 were at increased cancer risks.

University of North Carolina researchers reported that "radiation doses received at younger ages were not associated with cancer deaths. However, readings on radiation badges worn by workers when they were ages 55 and above were associated with death rates for cancer, and particularly for lung cancer."

British nuclear workers who were exposed to radiation before 1980 were at slightly elevated risks for premature dealth due to radiation exposure. However after new radiation exposure standards were imposed in 1980 the risk disappeared.

I have come to the conclusion that arguing the threshold hypothesis is probably not in the interest of nuclear bloggers. It is far better to argue that worker risk due to on the job exposure to radiation exposure posses at worst a very small risk compared to other on the job risks. Further radiation risks can be controlled and even eliminated by better safety practives, and radiation prevention technology.

An estimated 2.9 billion workers world wide face work related hazards in their workplaces. An estimated 775000 die every year of work related injuries.

Benzene exposure is a typical occupation related risk, although non-workers may also suffer from significant Benzene exposures.

Workers may be exposed to Benzene in:

* chemical laboratories
* pharmaceuticals manufacturing
* industrial plants that manufacture or use benzene
* oil refineries
* chemical and petrochemical plants (including some offshore installations)
* pesticide (herbicide & insecticide) manufacturing
* printing
* gasoline distribution
* pulp and paper manufacturing
* wood stain and varnish manufacturing
* synthetic rubber production
* adhesive production
* shoe and leather manufacturing

Workers may be exposed to Benzene from the following sources and activities:

* emissions from burning coal and oil
* motor vehicle exhaust
* spray painting
* industrial solvents (benzene in most petroleum solvents)
* evaporation from gasoline

The EPA (Environmental Protection Agency) estimates that 50% of the US population has been exposed to benzene through industrial sources such as oil refineries and chemical plants.

Benzene has been banned from most workplaces because it has been identified as a Class A carcinogen – a cancer causing agent. Even minimal exposure to this chemical can cause cancer and it may not happen until years after you are no longer working in the same occupation.

Workers who are at risk to Benzene exposure include:
Adhesive production
Barge Workers
Chemical Workers
Dock Workers
Gasoline distribution workers
Industrial plant workers who use solvents
Newspaper Press Workers
Offshore Workers
Paper and Pulp workers
Pesticide Manufacturing
Refinery Workers
Rubber Workers
Shoe / Leather workers
Synthetic Rubber Production
Truck Drivers

Any one who who works or spends time around the following is at risk for benzene exposure:
· Automotive gasoline fumes
· Industrial Solvents
· Oil and Coal Emissions
· Paint

Benzene exposure is a known causal factor for leukaemia, and other blood disorders. Blood related problems include damage to bone marrow (the tissues that produce blood cells). Aplastic anemia, excessive bleeding, and damage to the immune system (by changes in blood levels of antibodies and loss of white blood cells). Benzene causes both structural and numerical chromosomal aberrations in humans.

A French study reported that children who live close to service stations and auto repair shops children living within reach of either a gas station or a car repair shop are four times more likely to develop leukemia than other children. Benzene is used as an additive in crude oil based gasoline, and is being considered as an additive for ethanol. Researchers believe that there are 0.3-0.5 additional leukemia deaths per thousand people with 45 ppm-years of cumulative benzene exposure. There is no acceptably safe level for Benzene exposure.

The evidence is then that any health related risks related to radiation exposure can be controlled by improved safety practices, and improved radiation exposure prevention technology. On the other hand Benzene exposure appears far more difficult to control. Benzene is used as a octane increasing additive in gasoline, and environmental exposure to gasoline fumes appears to be a significant source of benzene exposure, Thus it would appear that benzene exposure poses a far more significant risk for environmentally related illness worker exposure to radiation does.

The case for nuclear power then is that workers risks of radiation caused illness is slight compared to the risk that workers and non-workers suffer from exposure to benzene.

Update on my views:  I have been thinking about my views on nuclear safety.  In effect I have changed my mind on a few issues, and neuanced other views.  , I have in effect withdrawn the argument on life span. I now simply note that the health effect nuclear worker radiation exposure at worst to be small. That evidence suggests that the effect might be confined to workers who are exposed at over 55, and that altering nuclear safety practices may make any radiation related health problem disappear. I also not that nuclear worker health research is unable to control for all independent variables, for example exposure to toxic substances. Thus the scientific validity of the research is open to question. However, in questions regarding human health it is better to err on the side of caution, therefore safety issues ought to be given high priority in nuclear research, best safety practices should be implemented in nuclear facilities, and mew safety technology once identified ought to be implemented by nuclear facilities. The NRC ought to follow up with individual licensees to insure that the highest possible safety standards are observed.

In addition, The NRC ought also to encourage safety monitoring of nuclear facilities by individual workers, Unions, and by citizens groups.

No comments:


Blog Archive

Some neat videos

Nuclear Advocacy Webring
Ring Owner: Nuclear is Our Future Site: Nuclear is Our Future
Free Site Ring from Bravenet Free Site Ring from Bravenet Free Site Ring from Bravenet Free Site Ring from Bravenet Free Site Ring from Bravenet
Get Your Free Web Ring
by Bravenet.com
Dr. Joe Bonometti speaking on thorium/LFTR technology at Georgia Tech David LeBlanc on LFTR/MSR technology Robert Hargraves on AIM High