The purpose of this procedure is to provide general guidelines for implementation of controls to reduce the risk of contaminating the workplace and the natural environment. This standards safety instruction applies to all project site workplaces for maintaining good house keeping.
Building construction and any other civil engineering works often involve redevelopment of land which has been previously contaminated by industrial processes once carried out on the site or by materials stored or dumped there.
In some places natural contamination may be present. Contamination may be a potential health risk to those working on site and to members of the public, unless adequate precautions are taken.
Hazard Identification and Risk Assessment
The issue of contaminated land is important because of the risk to human health either directly by contact with identified contaminated land during site related work or indirectly by migration of contaminants released by site related operations and potential damage to the environment.
Before work begins on any project developers should always consider the possibility of the ground and associated buildings being contaminated, and assess the risk to health and necessary precautions.
A full site investigation including analysis of soil and water samples and a geotechnical survey should be carried out. Initially, the responsibility lies with the client for carrying out such work, however, the main contractor must ensure this has been done and the survey results contained within the initial safety plan.
The assessment of the level and nature of contamination indicated by the survey will determination the extent of the precautions required. These may need to be reviewed as unexpected problems could arise during the progress of works.
a) Exposure to air borne contaminants.
b) Direct skin contact with contaminants.
c) Ingestion of contaminants
d) Skin absorption of certain contaminations.
e) Skin penetration through puncture wounds etc.
f) Asphyxiation due to gassing or oxygen deficiency.
g) Fire explosion due to the nature of contaminants.
h) Distribution of contaminants due to waste removal.
i) Uncontrolled release of contaminants into water courses, drainage systems and the like.
Control Measures to Avoid or Minimize Contamination Affects
Achieving a good standard of site control is one of the most important aspects of the list of measures to be taken. While the level of risk will determine whether the full range of such measures need to be provided, their principals should always be followed when working on a contaminated site.
Following the results of the survey taken and hazard/risk assessments made, the control measures selected should include as appropriate:
Defining the Contaminated Area
A designated dirty area as determined by the site survey should be clearly defined by suitable warning signs, and where considered necessary by the assessment of risk, the dirty area should be fenced off.
Standard of Hygiene
A good standard of hygiene must be maintained and where required an additional hygiene unit should be sited at the most convenient access point to the designated dirty area. The size of the unit will be dependent on the operations being undertaken and the number of persons required to work or pass in and out of the dirty area.
Due consideration should be given to the sitting of toilet/washing facilities, because of the importance of maintaining a high standard of hygiene.
Washing facilities should contain as a minimum:
- Hot and cold water
- Soap and scrubbing brushes
- Disposable towels/hand dryer
- Barrier creams
- Drain away from facilities
Eating and Smoking
No eating or smoking should take place in the designated dirty area.
Where deemed necessary a boot wash should be situated at the egress from the dirty area or outside the hygiene unit where one is required and should include where possible running water. Bristles either fixed or hand brush type should be provided to remove contaminated soil.
Confined Space Working
Where possible, exposure to contaminated materials should be minimized by, for example, lining the sides of excavations etc. with sheeting to reduce contact with spoil/contaminants. Otherwise all controls are as for confined space working and confined space work permit system will be used.
Control of Dust
Weather conditions such as hot, dry and windy, together with vehicle movements on contaminated sites can lead to the production of considerable amounts of dusts becoming airborne. These dusts can be blown around and off site putting the public at risk as well as site personnel. Precautions such as water sprays to damp down dust should be taken where appropriate.
Removal of Hazardous Waste
Detailed records on the disposal of hazardous waste will be necessary and should be discussed with the Waste Regulating authority prior to removal operations.
All open lorries or skips authorized to remove contaminated waste from sites should be sheeted. The entry to the site dirty area should where necessary be through a controlled gate.
Cleaning of Vehicle Cabs
The cabs of all vehicles working on a contaminated designated dirty area should be vacuumed at the end of each day to avoid the build up of contaminates which could place the driver at risk. The use of positive pressure cabs should be considered to prevent entry of contaminates.
Where required, wheel washing facilities should be provided; this facility should be sited on the boundary of the dirty area. Provision should be made for the collection and disposal of contaminated water and waste and this operation should be agreed with the Client and Local Authority / Water Authority.
Pollution of Watercourses
In planning and carrying out any works, adequate precautions must be taken to secure the complete protection of watercourses and water in underground strata against pollution. Any discharging of any contaminated water e.g. Wheel wash or groundwater control will require adequate provision, such as settlement lagoons to ensure that pollution will not occur.
The Local National Rivers Authority should be consulted in order to obtain approval, before discharging to any watercourse. Discharge into sewers will require the consent of the Local Authority or sewer owner.
The results of the survey, risk assessments, risk controls and assessments will determine the type of PPE to be used. This will include assessments made on the PPE itself for suitability to the requirements of the operations see section on PPE.
Health Surveillance and First Aid
The decision to implement health surveillance will be identified as part of the risk assessments.
First Aid provisions should be provided for workers on contaminated sites. First Aid arrangements will depend on the nature and degree of hazards at the site, the hours of work, availability of medical services and the number of workers on site. The trained first aiders should be aware of specific site hazards.
Employee’s hands should be checked on a regular basis for any reaction to contaminants, any bouts of nausea and giddiness should be reported immediately.
If persons are referred to Hospital, the Hospital should be informed as appropriate of the work and of any likely substances involved.
Eye wash bottles should be available.
Employees should be reminded of the advisability of maintaining immunization against Tetanus.
Site Visual Monitoring
A high standard of visual monitoring should be ensured, directed at the following matters:
i. Identification of areas of contamination.
ii. Identification of any spread of contamination between areas through underground pipes or trenches etc. during excavation works.
iii. Control of clean and dirty materials.
iv. Ensuring that safe working practices and protective equipment are being used.
v. The needs for specific air monitoring and any other samples required will be identified by the hazard survey and risk assessments.
Information, Instruction, Training and Supervision
Once procedures for work have been drawn up, information, instruction and training needs should be fulfilled so that employees know the risks and can apply the precautions required. It is important to reassure that they can work safely on site despite the dangers, provided proper precautions are taken and adhered to.
Experience has shown that when detailed information has been given to employees, backed up by strong supervision of the system, then a high level of compliance has been achieved. It is important to reassure personnel that they can work safely on site despite the dangers, provided proper precautions are taken and adhered to.
It is also important that all personnel who come to the site receive adequate information and where necessary, training. Details of training should be recorded.
Contaminated Land Checklist
a) Has a survey of the land been carried out?
b) Has a written Risk Assessment been prepared?
c) Is the contaminated area clearly defined and warning signs posted?
d) Is adequate hygiene provided and maintained.
e) Is eating and smoking prohibited in all dirty areas.
f) Are adequate boot wash facilities provided and maintained.
g) Are adequate precautions taken to minimize exposure to contaminants when working in confined spaces?
h) Is dust suppression adequate?
i) Is waste removal by registered carrier?
j) Are Waste Transfer Notes/Consignment Notes up to date and available for inspection?
k) Is the containment of waste during transportation adequate?
l) Are vehicle cabs being maintained in a clean condition?
m) Are wheel wash facilities adequate and being maintained.
n) Have all watercourses/sewers been protected against accidental pollution.
o) Are all persons working in contaminated areas aware of the hazards and provided with the necessary PPE.
p) Have all persons received adequate information and training.
q) Are all persons wearing the necessary PPE?
r) Are First Aid facilities provided and adequate?
s) Is health surveillance carried out on site?
t) Has National Rivers Authority been notified to gain approval for any controlled discharge?
u) Has the Local Authority/sewer owner been notified to obtain consent to discharge.