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                            

- Diesel exhaust

- Ethylene oxide

 - Nickel

-Involuntary smoking (Passive smoking) -Vinyl chloride

-Radon and its decay products

So what do I do in the home and the workplace?

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/

Sources of information:

1) NEBOSH: International diploma on Occupational health and safety:- Unit B2  - Toxicology and Epidemiology.

2) HSE website

3) Wikipedia:- “Carcinogen”