Confidential Draft
TECHNICAL REPORT
Health, Safety and Environmental Policy Guideline
Prepared by:
Mercury Technology Services
23014 Lutheran Church Rd.
Tomball, TX 77375
S. Mark Wilhelm, Ph.D.
Prepared for:
Petroleum Development Oman
PO Box 81
Muscat 113
Sultanate of Oman
Mr. Nasser Naamani
W. J. Towell & Co. (LLC)
P.O. Box 1040 Ruwi
Postal Code 112
Sultanate of Oman
Mr. Philip Goddard
March 20, 2003
Table of Contents
Page
1.0 INTRODUCTION 3
2.0 HEALTH, SAFETY and ENVIRONMENTAL POLICY 5
2.1 Risk Assessment
2.2 Worker Health and Safety
2.3 Environmental Protection
2.4 Training
2.5 Analytical Basis
3.0 HEALTH AND SAFETY 10
3.1 Routes of Worker Exposure
3.2 Exposure Limits
3.3 Personal Protective Equipment
3.4 Diagnosis and Treatment of Exposed Workers
4.0 ENVIRONMENTAL ISSUES 20
4.1 Mercury Emissions to Water
4.2 Mercury Emissions to Air
4.3 Mercury Emissions Via Solid Waste Streams
5.0 TRAINING 28
6.0 CONCLUSIONS and RECOMMENDATIONS 29
Appendix A - Mercury in Hydrocarbons; Chemical Background A1
Appendix B - PDO Background B1
Appendix C – Canadian Guideline for Mercury, Questions and Answers C1
Appendix D – U.S. NIOSH Guideline for Mercury Vapor D1
Appendix E – U.S. OSHA Guideline for Elemental Mercury E1
Appendix F – Occupational Health Guideline for Organo (Alkyl) Mercury F1
Appendix G – Emergency Treatment G1
Appendix H – Employee Hygiene Facility H1
Appendix I – Personal Protection Equipment G1
Appendix J – Mercury Training Viewgraphs H1
1.0 INTRODUCTION
Mercury Technology Services (MTS) was requested by Petroleum Development Oman (PDO) to compile information concerning mercury-related health, safety and environmental (HSE) concerns associated with natural gas production and processing in Oman. Of interest were the methods to minimize risks associated with mercury in produced fluids. MTS provided technical services to PDO under contract to W. J. Towell and Company (WJT, principal contact Philip Goddard).
Mercury is a trace component of fossil fuels including coal, crude oil and natural gas. In hydrocarbon processing and petrochemical manufacture, mercury in process feeds can contaminate equipment and can segregate to sludge and other waste streams. Opportunities therefore exist for workers to be exposed to mercury and its compounds in routine repair, maintenance and inspection activities and when handling process fluids and waste materials. Because of mercury’s toxic nature and its harmful effects on the environment, such activities must be structured to prevent acquisition of mercury by workers, to avoid contamination of processing facilities and to avoid escape of mercury into the environment.
This document is designed to provide technical information and advice to assist managers and responsible health, safety and environment (HSE) personnel in the oil and gas production and processing industries to formulate policies and procedures that minimize the detrimental impacts of mercury on company operations. Such policies are necessary to reduce health risks and to avoid liabilities associated with inadvertent discharges of mercury to the environment.
Mercury is the primary focus of the following discussion although it is acknowledged that petroleum also contains other toxic components that are also problematic. The primary reasons for this focus are that mercury is a well-known constituent of oil and gas, its properties are unusual compared to the other metals and facile avenues of exposure accentuate the toxicity of mercury. In addition, mercury is one of a special class of pollutants that includes those simultaneously toxic, persistent and accumulative in the environment. For these reasons, mercury deserves special attention.
Companies operating oil and natural gas production and processing facilities (gas and oil production systems, primary field fluid conditioning, gas separation/liquefaction, refining, transportation and storage facilities) should be aware of the concentration of mercury in processed/transported fluids. From this knowledge decisions can be made concerning the likelihood and magnitude of contamination in the workplace and steps can be taken to mitigate the impact of mercury on workers, equipment and the environment.
The consequences of inadvertent exposure of workers to mercury, dispersal of mercury in processing facilities or inadvertent discharges of mercury to the environment are universally detrimental. Clear incentives exist to adopt plans and policies that minimize the risks and problems that accompany mercury’s presence in hydrocarbons. This guideline document compiles and discusses the technical aspects of mercury found in petroleum and natural gas so as to assist the development of engineering practices and operating policies that are based on a comprehensive understanding of the existing science and the current successfully-applied practice within the oil and gas industry.
Mercury exists as more than one chemical species in oil and gas. Background information regarding the chemistry of mercury in hydrocarbons and the distribution of mercury species in production and processing systems is provided in Appendix A. The technical approach to HSE policy should take into account the chemical and physical properties of the major mercury species and their individual and collective toxicologies. It is not possible to lump mercury in hydrocarbons into one general chemical category and thus formulate policies based solely on total mercury concentrations. The better approach is to recognize mercury’s chemical diversity and then to accommodate species-dependent variety in procedures and policy.
Details concerning PDO’s gas production and processing operations in Oman are contained in Appendix B. Mercury was found as a trace constituent of gas produced in Central Oman in 2001. Efforts have been made to measure the concentrations of mercury in various hydrocarbon streams associated with the production and processing systems. Details of the analytical measurements are contained in Appendix B. It is anticipated that the concentration of mercury in produced fluids will increase in the future due to increased production from newer fields having higher mercury concentrations.
A secondary purpose of this guideline document is to provide some quantity of background information for use by HSE personnel. The selected information in the Appendices covers several aspects of toxicology, mercury safety plans, medical treatment and other areas that are considered essential reading prior to formulation of company polices and operational procedures. A good overview of health and safety concerns, in a question and answer format, is contained in Appendix C. Although this report is directed to the managerial level, it should serve as a reasonably comprehensive reference document for those employees tasked with implementation of policy.
2.0 HEALTH, SAFETY and ENVIRONMENTAL POLICY
If mercury is a constituent of processed hydrocarbons, then plans for dealing with its consequences should be incorporated into a company’s existing HSE policy framework and into work procedures for specific jobs in which contact with mercury in hydrocarbons is possible. Such incorporation should be based on sound technical information with acknowledgement of the limitations of current understanding. A mercury-specific process hazard management strategy is an integral part of a comprehensive process safety and environmental protection program.
Some key elements of company HSE policies affected by mercury’s presence in processed fluids typically include:
· Risk Assessment
· Worker Health and Safety
· Environmental protection
· Training of personnel
· Analytical Basis
2.1 Risk Assessment
Risks associated with producing, transporting or processing petroleum or natural gas containing mercury fall in several categories. Of primary importance is the risk to workers who handle fluids or repair and maintain equipment. Mercury is highly toxic and has a propensity to accumulate in and contaminate storage tanks, pipelines and processing equipment. Assessing health risks to workers is a reasonably straightforward exercise if a concerted effort is made to acquire the analytical information necessary to make sound judgments.
Aside from worker health and safety, there are clear economic risks associated with mercury in process feeds. The economic risks derive from mercury’s lowering of product quality, potential negative interactions with equipment (corrosion and embrittlement of metals) and the liabilities derived from its pronouncedly detrimental impact on the environment. Having mercury in process feeds causes difficulties with normally routine repair and maintenance activities and leads to generation of waste streams that may be difficult to dispose of. Mercury also can damage equipment under certain circumstances.
Steps can be taken to minimize risks from an understanding the toxicological, chemical and physical properties of mercury and mercury compounds, determination of the possible exposure pathways in the work place and adopting policies and procedures that mitigate worker exposure and dispersal of mercury to products and the environment.
Both human-related and economic risks generally are proportional to the concentration (total) of mercury in processed hydrocarbons. In general, the risks associated with mercury can be categorized according to total mercury concentrations acquired by routine analytical procedures having documented quality assurance. The arbitrary categories are as follows:
· Less than 10 ppb liquid (<5 mg/m3 gas) – Low Risk
· Between 10 and 100 ppb liquid (5-50 mg/m3 gas) – Medium Risk
· Greater than 100 ppb liquid (>50 mg/m3 gas) – High Risk
In the low risk category, speciation of mercury compounds is not essential given the analytical uncertainties. HSE policy in this category should focus on monitoring the total amount of mercury in key process streams to ensure that the concentration does not increase over time. In addition, workplace monitoring should be directed to process locations known to concentrate mercury (cryogenic process sections for example).
In the medium risk category, limited operational speciation of the chemical forms of mercury is required to determine the percentage of elemental mercury in the measured total concentration. If the elemental form comprises over 75 percent of the total, then the policies adopted for worker health and safety should be directed to avoidance of inhalation and dermal absorption of the elemental form. In the medium risk category, the locations of possible accumulation of mercury also are more numerous and the monitoring requirements in the work place need to be more frequent and detailed. At this level some attention must be paid to the possibility that organic mercury may be present in liquid process fluids.
Having total mercury concentrations in excess of 100 ppb requires detailed speciation of compounds, frequent monitoring and stringent controls on activities that could expose workers to mercury vapors and dermal contact with fluids. Environmental protection is more difficult in this category and numerous process streams require scrutiny for mercury content.
2.2 Worker Health and Safety (see Appendices D – F)
Mercury is poisonous to humans and can cause neural damage or even death from either acute or chronic exposure. Because of the subtleties of mercury poisoning, toxic influences to neural function can go unnoticed for very long periods of time, if they are detected at all. Chronic, low level exposures may require years to diagnose unless exposure risks are apparent and efforts are made to biologically evaluate those potentially affected. Chronic mercury toxicity is extremely difficult to diagnose from symptoms in their early stages. At the point of conclusive symptomatic diagnosis, neurological impairment is usually at an advanced stage and remediative therapies are mostly ineffective.
The discovery of significant quantities of mercury in fossil fuels is not a recent occurrence and, in spite of the fact that mercury is abundant in some major fields, major health deficiencies have not been documented in large classes of workers in the petroleum industry. This fact is reassuring, however, workers can be exposed to mercury and mercury compounds in activities such as equipment cleaning, repair and inspection, during hot work on contaminated equipment and piping, and in a variety of other activities. Acute high-level exposures that produce obvious detriment in workers are rare but can occur under certain circumstances (vapor monitor malfunction, vessel entry, non-monitored hot work, equipment maintenance).
Avoiding exposure to mercury, in most maintenance and inspection activities, is readily accomplished if some fairly simple steps are taken to identify those situations in which exposure is possible, and by provision of commonly available equipment for worker protection from inhalation or dermal absorption. Incidents of inadvertent exposure are more likely in situations that are not routine or that involve unsupervised or contract personnel. With proper procedures and plans, protection of workers can be achieved without tremendous expense or operational impediment.
Policies designed to ensure the health and safety of workers should be based on a thorough chemical analysis of process streams that provides concentration of total mercury and some information on concentrations of the chemical forms of mercury. Computational methods can supplement analytical data to predict locations of accumulation. Atmospheric monitoring of mercury vapor in work areas is essential to identify potentially hazardous conditions. With this information (analytical, air monitoring, speciation), prevention of inhalation and/or transdermal absorption of mercury can be accomplished using conventional protective equipment. Procedural details should address PPE logistics to make sure that protective equipment is readily available when needed and easily replaced.
2.3 Environmental Protection
Mercury is universally detrimental to the environment and discharges should be minimized or eliminated to the extent possible. The trend in mercury discharge regulations, whether to air, water or solid waste streams is toward greater restriction. Producers and processors of petroleum that contains mercury should be aware of its presence and should take prudent steps to ensure environmental impacts are as minimized and well within existing regulations.
Mercury, unlike many other pollutants, does not degrade to benign forms over time. Thus one cannot rely on naturally occurring processes to mitigate the impact of mercury on the local environment. Spilled elemental mercury, for example, will remain in soil for hundreds of years without major degradation.
A major effort is underway internationally to reduce anthropogenic mercury discharges to the environment. There are a myriad of reasons as to why this is the case but the major reasons stem from the toxicity of methylmercury to humans and piscivorous mammals in general and to inorganic mercury’s toxicity to aquatic organisms. No attempt is made in the present context to review the geochemistry of mercury that leads to the conclusion that the mercury originating from human activities should be substantially reduced or eliminated. Rather, the reader is referred to any of the major reviews on the subject for a thorough discussion (U.S. EPA Mercury Study Report to Congress, United Nations Environment Programme (Chemicals), Global Mercury Assessment).
It is undisputed, however, that the majority of the mercury that enters the global mercury cycle from human activities comes from combustion of waste and fuels. Discharges of mercury to water and surface mercury waste accumulations are severely restricted and regulated by governments because of mercury’s toxic and persistent nature. It is incumbent upon companies to account for mercury in all produced waste streams and in products sold commercially, to comply with regulations that apply to emissions and to adopt policies that protect the environment, even in the absence of applicable guidelines.