Carcinogenic - what is it and how does it affect the
workplace and your home?
Article by: J.Krog
We use chemicals every
day in the workplace and in our homes but did you know that some are classified
as carcinogenic? But what does carcinogenic mean and how does it affect the
body?
Carcinogenic is a
chemical which is believed to be capable of causing cancer in humans. But lets
step back and have a look at cancer in humans, and how does it happen?
A cancer is a growing mass of non-productive tissue that is
relentlessly progressive, ending in the death of the individual. This tissue
growth is termed a malignant tumor and can spread within the body via the
bloodstream or lymphatic system. This process, termed metastasis, leads to the
formation of other small tumors scattered widely throughout the body.
These new tumors can grow into nearby tissues and destroy
them as a consequence, by a process termed invasion. Metastasis and invasion
are the two characteristics that distinguish malignant tumors from those
classified as benign.
What is benign and malignant mean?
Benign tumors usually grow very slowly, remain localized and
their cell structure is often similar to the cells of origin. Malignant tumors
grow rapidly without restraint, spread into surrounding tissue and have their
own cell structure, unlike the cells of origin. The term cancer is used to
describe the formulation of malignant tumors. The carcinogen has the ability to
produce malignant tumors. The agent can either be physical, chemical or viral.
In terms of occupational cancer, the carcinogenic agent will be physical or
chemical.
Formation
of Cancerous Cells
It is
generally accepted that cancerous cells are formed by the carcinogen attacking
the mechanism which controls the reproduction of normal cells. The toxic action
of carcinogens differs from 'ordinary' toxic action:
They upset the fundamental cell reactions within the cell
structure, whereas ordinary toxic substances mainly upset the general metabolic
processes which prevent cells from functioning normally. They evoke
irreversible effects which continue after exposure to the carcinogen has
ceased. The action of ordinary toxic agents usually stops when the exposure
ceases, and recovery generally follows. The effects of a carcinogenic agent
will not appear for many years after exposure. The period of time is its
latency period. Periods between 5 and 50 years are given for different agents.
During this time, there is little or no warning of the eventual tragic outcome.
'Ordinary' toxic agents can evoke an acute response and also a chronic
response. The particular point made above highlights the importance of strict
control in the use of carcinogenic substances. Once the symptoms have been
diagnosed, the problem will often have reached the point of no return.
Carcinogens
interact with the genetic material of the cell, the DNA, causing structural and
functional alterations which cause the cell to grow in an uncontrolled manner.
This damage
to the DNA may be repaired by enzymes that exist within the cell nucleus.
However, in
cases where this repair is not carried out effectively, the cell is
significantly altered and acquires properties which were absent prior to the
damage.
In some instances, these new properties may be passed on to
daughter cells during cell division. This hereditary transmission of new
characteristics is an indication that the cell has been mutated, and the event
that brings about this change is termed a 'mutation'
The process
of mutagenesis, therefore, is considered the first step in the process of
carcinogenesis, and many short-term tests for carcinogenicity are based on the
ability of a chemical to induce mutations.
Generally,
carcinogens and mutagens are categorized as such on the basis of human or, more
likely, animal data.
The
International Agency for Research on Cancer (IARC) classifies substances as:
*'Carcinogenic
to humans' (human evidence)
* 'Probably
carcinogenic to humans' (good animal evidence)
* 'Possibly
carcinogenic to humans' (less good animal evidence)
So which chemicals
are carcinogenic?
Yes you probably guessed it but the number one offender in
the non-occupational category of carcinogenic chemicals is cigarette smoke of
which the effects are well documented and advertised (just look at your
cigarette box). However did you know that Cooking food at high temperatures,
for example braaing meats, can lead to the formation of minute quantities of
many potent carcinogens that are comparable to those found in cigarette smoke?
Charring of food resembles coking and tobacco pyrolysis, and produces similar
carcinogens. Pre-cooking meats in a microwave oven for 2–3 minutes before
grilling shortens the time on the hot pan, and removes heterocyclic amine (HCA)
precursors, which can help minimize the formation of these carcinogens.
Reports from the Food Standards Agency have found that the
known animal carcinogen acrylamide is generated in fried or overheated carbohydrate
foods (such as French fries and potato chips).Studies are underway at the FDA
(Federal Drug Administration in the USA) and European regulatory agencies to
assess its potential risk to humans.
Occupational carcinogens
Did you know that Shiftwork that involves circadian
disruption in women has been found to be carcinogenic, in that in can cause an
increase in breast cancer, this was declared by the World Health Organization
in 2007? It is therefore important for employers to review and monitor the
schedules of women working shifts.
Below is a list of known Occupational
carcinogens
-Arsenic and its
compounds
-Asbestos
-Benzene
-Beryllium and its compounds
- Cadmium and its compounds
- Hexavalent chromium (VI) compounds
- Ethylene oxide
- Nickel
-Involuntary smoking (Passive smoking) -Vinyl chloride
-Radon and its decay products
In the home?
First of all before you
buy any chemical look at the label on the back, or the leaflet that is
contained in the box. Should the following sign appear?
It could be classified as a carcinogenic, and
must be assumed to be carcinogenic.
Also have a look at the
chemical composition and list of ingredients, should it contain one of the
chemicals listed above, assume it to be carcinogenic.
Try as far as possible
to use an alternative, if none is available make sure you follow the directions
on the bottle in terms of mixing, use of personal protective equipment, storage
and disposal. Most of all keep the chemical away from young children!!!
In the workplace
Consult with a health
and safety professional who can perform a hazard identification and risk
assessment process (HIRA), to determine hazards within your processes and risks
associated with it.
During the HIRA
process, gather information on all the chemicals used within the process -
refer to the Material Safety Data Sheet (MSDS) which will list the toxicology
information on the product in use. It will also list the risk phases of the
chemical, which gives specific toxicology information on the chemical in use.
Remember to look at all hazards chemical, biological, and physical to determine
carcinogenicity.
Again try to find a
substitute, and if none is available pay careful attention to the control and
use of the chemical. Ensure that regular medical testing and observation is
conducted, this will highlight possible problem areas and adequacy of controls.
Follow a rigorous
training programme with all employees, ensuring that they understand the risks,
controls and use of personal protective equipment.
For more information
please visit the following websites:
1) U.S. National Toxicology Program's Report on
Carcinogens: http://ntp.niehs.nih.gov/
2|) HSE Website: http://www.hse.gov.uk/cancer/
1) NEBOSH: International
diploma on Occupational health and safety:- Unit B2 - Toxicology and Epidemiology.
2) HSE website
3) Wikipedia:-
“Carcinogen”
Hi Jacques, wow I never thought that we encounter so many carcinogins in our day to day lives AND the negative long term effect of them invading our bodies.....thanks for making me more aware!
ReplyDeleteGreat work J.K, congradulations on such an informative site. Its a breath of fresh air
ReplyDelete