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What is their environmental policy?

This is a very important area for DSS again because of the nature of the industry they are working in and the products and raw materials that they are working with. DSS's environmental policy is driven, in part, by a need to be socially responsible, efficient and to reduce costs where possible. There are also requirements placed on them by legislation and by regulation by the HSE, Environment Agency and the EU.

DSS has to carry out a number of activities to determine the risk that their activities pose to the environment and to the local community. One method used to determine risk is the Tolerable Risk Assessment Procedure (TRAP). Any production activity, especially one involving dangerous chemicals, involves some element of risk. A firm like DSS has to make sure that the risk they impose on the environment and the local community is as low as practically possible.

Monitoring production 24 hors a day is an essential part of the business. Images: Courtesy of Degussa AG. Copyright held by Degussa AG.

Part of the problem is in deciding the extent of the risk and what is tolerable. It is accepted that there is always a level of risk involved when handling materials and processes within the chemical industry. It is necessary to be able to demonstrate that these risks have been reduced to a minimal level, and that this level is tolerable for both the employees of the company and those outside the company. In order to demonstrate a level of acceptable risk, DSS have developed a risk graph, matching the consequence of an event against the residual risk.

There are a number of questions it has to ask itself:

• What is the potential consequence associated with an event occurring?
• What is the cause of the event?
• How likely is this to happen?
• Is this event frequency acceptable?
• What measures can be taken to reduce the event frequency or the consequences if the event occurs?
• Are the risks now tolerable? Are there any other risk-reducing factors that can reasonably be taken?

Almost every aspect of a host of different scenarios has to be considered, analysed and planned for. For example, the Middlesbrough Football Club stadium is very close to the whole industrial complex. What would happen if 20 tonnes of chemicals escaped from the plant; where would it go? What are the likely concentrations that would be involved? What would happen if the stadium was full with supporters? Would there be a difference if it was the daytime or at night?

DSS has to make a decision about what level of risk is acceptable and what is not. A risk factor of 1:10⁵ (100,000) is deemed as acceptable; that is 1 in every 100,000 years. Anything less than that is considered to be unacceptable. It should be pointed out that, as an example, the tolerable risk relating to an event causing a fatality is far less than the risk the general public put themselves at when driving a car.

Once the risk has been identified, systems have to be put in place to prevent that risk from happening. The company then has to carry out an analysis of the reliability of these systems - alarms, instrumentation and so on. Reliability data on such systems is available from a number of sources. For example in literature, from the HSE or from consultancy companies for which DSS might have to pay.

Although there have been no significant consequence events at DSS, the problems that can be caused by the failure of such instruments were seen in 2005 when an explosion at an oil storage depot in Hertfordshire in southern England led to 43 people being injured, 2,000 homes evacuated and a fire which burned for over 32 hours. One of the causes of the explosion was the failure of a gauge which got stuck and an alarm that was supposed to have been triggered, which also did not work.

It is not enough for DSS to say they have been thinking about safety and systems - they have to prove it. EU guidance documents called IEC 61508 and 61513 relate to the chemical industry. To comply with these documents, DSS has to demonstrate that it has reduced risk to a minimum that could reasonably be expected. They have to demonstrate that the cost of reducing it further would be disproportional to the marginal benefit arising from that effort. DSS will also have to prove that they have thought about other aspects of their business and offer sound reasons why they have decided not to implement policies or systems to deal with those issues.

DSS always understands, despite these considerable steps taken to reduce risk and maintain safety, that whilst the frequency rates or the risk might be very low indeed, a serious incident could happen tomorrow!

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