Land Contamination: Technical Guidance on Special Sites: Acid Tar ...

• all personnel should follow a decontamination process that should consist of, at aminimum, the removal of overalls and boots, and the washing of hands and face.The relative importance of each of the above will depend to some extent on the kind of acidtar (e.g. whether there was pre-treatment to reduce acidity) and the age of the deposit. Withregard to stability issues, the lagoon surface may be relatively solid, especially during winter,while in summer, warming of the tars will lead to softening and expansion, leading to a loss ofbearing capacity and surface spreading. If there is sufficient local knowledge about aparticular site (e.g. if it is known to have been covered and is now tracked over by various sitevehicles) then it may be possible for staff to walk on the site surface. However, if there islimited/no local knowledge then sites must be considered unsafe and further informationshould be gathered to determine whether the site is safe to walk on.Further practical risk management issues to consider when undertaking site works on acid tarlagoons include the following:• access to the lagoons themselves should be restricted to prevent personnel fromwalking across the site and limited to those working on the site.7.3.2 Equipment• PPE should be worn at all times to protect the skin from acid burns and contact withhydrocarbons and heavy metals. In many cases the pH may be 2 or lower and in somecase below pH 1. Protective equipment should include acid resistant boots togetherwith disposable overalls and gloves as a minimum. On some sites the tars may be of amore hazardous nature requiring the use of gloves, boots, overalls etc. made ofchemical resistant (as well as acid resistant) materials (e.g. chlorinated polyethylene,viton, neoprene or PVC);• eye protection should also be worn. Where vapours are not a problem safety gogglesmay be sufficient. Full face masks may need to be worn dependent on the results ofvapour monitoring. Of particular concern are acidic vapours, also hydrogen sulphideand sulphur dioxide as well as lighter hydrocarbons which may be present within thetar.As indicated previously, Table B.1 in Appendix B provides a list of contaminants that couldbe present within acid tar lagoons and this can be used in health and safety planning.R&D <strong>Technical</strong> Report P5-042/TR/04 47