[MUSIC] Bitumen has many advantages in its applications, not least the fact that it is a good waterproofer, a good agent and a poor transferer of heat. However, when working with bitumen, these exact same characteristics become a disadvantage. If bitumen sticks to your skin, it's incredibly difficult to remove, cannot be washed off, and stayed hot on your skin for a long time. Therefore, it's critically important to have a clear understanding of the hazards associated with bitumen and the appreciation of the risks can be adequately managed. This module will aim to guide you through a broad appreciation of the health and safety implications of bitumen and highlight where the key risks might lie. Bitumen is thermoplastic in nature. That it is a bitumen becomes more liquid like with increasing temperature and conversely more solid like with reducing temperature. Therefore, bitumen is generally used at very high temperatures. Typically in the range of 150 to 180 degrees Celsius. To pour this elevated temperature into some context, just think about normal body temperature. This is in the range of 36.5 to 37 degrees Celsius. Now taking a shower at 50 degrees C over 15 minute period is likely to create burns requiring hospital treatment. In other words, that's only 14 degrees Celsius above body temperature. Now consider the implications of boiling a kettle of water. The water is boiling at 100 degrees C, some 63 degrees stable body temperature. Now everyone is aware of the risk with water at this temperature, and would never consider exposing their skin to it. Such an action would certainly result in significant burns. Most likely requiring skin grafts and resulting in some psychological trauma. Bitumen exposure during manufacturing would involve temperatures in the region of 160 to 190 degrees C, depending upon the type of bitumen. In other words, in excess of 140 degrees C above body temperature. Remember, only 14 degrees C exposure over body temperature can result in hospital treatment. How much more extreme at 140 degrees C hotter? The impact is not just physical pain and disfigurement but also psychological trauma as well. So it's absolutely critical to treat hot bitumen with respect and not to be complacent. So these examples illustrate that the main hazard associated with bitumen is the temperature at which it is used and transported around. Without doubt the risk of exposure to this high temperature hazard Comes chiefly when moving bitumen around or transferring from the tanker to the storage tank. Also of course when sampling and testing the bitumen material. If nothing else, please keep this hazard at the fore front of your mind at all times when in the vicinity of bitumen. One misconception that is all too common is the belief that bitumen and tar are the same thing. It's true to say that some of the physical characteristics are very similar, and that they both provide good adhesion, and good waterproofing. However chemically, they are significantly different and the health implications resulting from that are also significantly different. The International Agency for Research into Cancer, so called IARC have carried out a wide ranging evaluation of global studies culminating in the IARC Monograph, volume 103. This review considered studies looking at exposure data, studies of cancers in humans, study of cancers in experimental animals, and mechanistic studies. In other words, mutations occurring in the human body on a microscopic scale. It must be understood that the outcome of the monograph is a hazard rating and not a risk rating. And so illustrates the cancer hazard, around which the exposure risk can then be identified and managed. In the case of monograph 103, paving grade bitumen emissions have been classed as 2B or possibly carcinogenic. To put some context into this rating, it's important to understand the scale of the ratings. So a plus one means the agent is carcinogenic to humans. And for example in this class, we see diesel exhaust fumes and alcoholic beverages. In class 2A, this means the agent is probably carcinogenic to humans. And we see examples, such as fumes from high temperature frying or consumption of red meat. Class 2B, means the agent is possibly carcinogenic to humans. And in this class we see examples like coffee, pickled vegetables or low frequency magnetic fields. For class 3, the meaning is the agent is not classifiable as to it's carcinogenicity. For example, we see fluorescent lighting or chlorinated drinking water. And class 4, this means the agent is probably not carcinogenic to humans. The outcomes of the IARC Monograph provides the user with some quantified guidance as to the potential consequence. Coupled with an appreciation of the likelihood of exposure, it's enabled an understanding of risk within the particular process. Remember, this is focused on exposure to bitumen fume. The bitumen itself is considered as inert in its ambient state. One well recognized hazard naturally occurring in bitumen is hydrogen sulphide. This gas is potentially released from the bitumen into the vapor. Now the amount or concentration will vary significantly depending upon the type of bitumen, the temperature and the agitation, and also the ambient conditions above the bitumen. In other words, it is difficult to be too prescriptive about the risk without clearly identifying the specific conditions. By far the most significant concentration of hydrogen sulphide is likely to be developed in the vapor space of storage tanks and delivery vehicles. In well ventilated areas, the hydrogen sulfide tends to disperse into the air. Hydrogen sulfide is a gas, heavier than air, and can impact on the nervous system in high concentrations and can also contribute to the flammability in the vapor space of tanks. Regarding the impact on humans hydrogen sulfide dulls the senses. For this reason at very low concentrations, hydrogen sulfide can recognized by its familiar bad egg smell. However, as the concentration increases, the gas reduces the smell sensitivity and you then cannot smell it. So reliance on smell detection is not at all effective, at very high levels i.e., 100 of ppm, the effect on the nervous system can be so extreme as to make the individual unbalanced and even unconscious. At even higher concentrations the impact can be fatal. The impact of the hydrogen sulfide is in the vapor phase, i.e., in the fume and not the bitumen itself. Therefore, the risk assessment needs to focus on exposure to fume. More specifically in areas where fume can concentrate up. In other words, in enclosed vapor spaces. Therefore, care must be taken when opening tanker lids or tank lids as there could be a rush of fume that has relatively high levels of hydrogen sulfide. Likewise, where tanks need to be entered. For example, in maintenance or cleaning it's critically important to ensure the tank has been well ventilated purged and gas tests completed before anyone considers tank entry. Moreover continual monitoring of the air space must employed. Potential to give off hydrogen sulfide will vary from source to source and generally the risks associated with general use are very low. Factors which can increase the potential for release of this gas include high temperature, increased agitation and poor ventilation. Essentially, this registration is applicable throughout Europe to ensure that all hazards reflective be identified. And the scale of the potential impacts effectively evaluated. In all industries, it is mandatory that information is shared amongst other players in the industry. As such, the assessment for bitumen has been coordinated by Eurobitume. The results of all the assessment is a dossier that is submitted for registration. Once this has been reviewed a REACH registration is recorded. So what have we seen through this review of bitumen health and safety. First and foremost bitumen itself at ambient temperature is inert and safe to handle. The key hazard is associated with handling the bitumen at elevated temperatures. The magnitude of the temperature must be acknowledged to appreciate the level of risk likely for any scenario when handling liquid bitumen. With regard to impact on health, we have seen that IARC have classed the bitumen fuel from paving grade bitumen at level 2B, which means that it is possibly carcinogenic in the same class as coffee and pickled vegetables. One hazard to be aware of when carrying out your risk assessment is the potential presence of hydrogen sulphide, specifically in areas of restricted vapor space. In well ventilated areas this tends not to be an issue. This can be affected by temperature, agitation, level of ventilation, and surface area to volume ratio. Finally, bitumen in Europe is compliant with the REACH registration process which is being coordinated by Eurobitume. [MUSIC]
