Identification, assessment, control and follow-up of benzene exposureEllen Katrine Jensen, 5th of Nov 2015Norwegian oil and gas association, Network industrial hygiene

Recommended guidelines for benzene

• These guidelines have beenprepared as part of the industryproject on the chemical workingenvironment in the oil and gasindustry.

• They have been prepared with broad-based participation by interested parties in the Norwegian petroleum industry

2

Benzene in the petroleum industry

• Occurs naturally in oil and gas reservoirs

• Follows the hydrocarbon (HC) production chain

• Crude oil in offshore production: 0-1 % benzene

• Natural gas condensate: as high as 10 % benzene

• Produced water: benzene occur in solution

• Refineries: vary from 0 to 60 % in different production streams

• Other benzene sources: as a pollutant in solvents, paint and oil-based mud containing aromatics.

3

Regulations – occupational exposure limits (OEL)

• Norway Benzene 1 ppm (8 hour)

0.6 ppm (12 hour)

Stricter benzene OELs are used by several oil and gas companies:

• ACGIH Benzene 0.5 ppm (8 hour)

0.3 ppm (12 hour)

2.5 ppm (STEL, 15 min)

SPMA in urine 25 μg/g creatinine (BEI)

4

How do we control benzene exposure?

• Design: Closed and automated systems (containment)- sampling, draining, cleaning

Locate vents to safe areas- prevailing wind direction, no workplace

• Operation & Maintenance (O&M):

Risk assessment (measurements + +)

Risk control (PPE + +)

Verification of barriers

• Turnarounds: Same as O&M, prepare for high risks when opening closed system, entry, cleaning etc

5

Risk assessment - 1

• Identify sources process system, support system, waste stream, equipment

• Identify job tasks involving possible exposure opening HC equipment, entering tanks, sending/receiving pigs, changing and cleaning filters etc

• Identify particularly exposed groups process operators, drilling personnel, tank cleaners, laboratory technicians, deck crew on ships etc

6

Risk assessment - 2

• Perform occupational hygiene measurements

Aim: document the level of exposure for SEGs, input when choosing PPE, verification of effect of barriers

• Strategy, basic survey based on validated sampling methodology, statistical assessments

• Modelling (earlier exposure, scenarios)

• Direct reading instruments (immediate feedback of concentration level when opening HC systems, entry etc)

• Personal air monitoring with adsorption tube + pump, dosimeter (Stami, NIOSH)

• Biological exposure monitoring (SPMA in urine), total exposure, verification of effect of barriers

7

Risk control - 1

• Technical measures Extraction ventilation (see also Design)

• Procedures and safety instructionCategorizing equipment, job tasks, direct reading instruments, PPE, training and information

• TurnaroundsReview all jobs with respect to exposure and protection. Plan ready prior to turnaround to allow for implementing measures and training.

• Information and trainingExposure risks, measures to control, documentation

8

Risk control - 2

• Personal protective equipmentChoice of PPE by competent personnel (+ operations, safety delegate)Respiratory protection (fit-tested), routines filter change and maint.Nitrile gloves, specification of penetration timeDocument barrier effect (biological monitoring)

• Exposure surveillanceRisk assessment indicate benzene monitoring measurement program (periodic occupational hygiene measurements)

• Health surveillanceSuitable health checks where available, register employees exposed to benzene

9

Competence

• Qualified occupational hygienist

• strategy

• risk assessment

• measurement

• Validated methods

10

Thank You

11