Evaluation to Identify Benzene Safe Concentration in Oil and Gas processing Facility in East Java Area Due to Process Fugitive Emission

Benzene is an organic chemical compound with the chemical formula C6H6. The benzene molecule is composed of six carbon atoms joined in a ring with one hydrogen atom attached to each. Acute benzene exposure can cause central nervous system depression. Longterm exposure can result in depression of the blood-forming system and may increase risks associated with anemia and leukemia. The purpose of this research is to identify benzene safe concentration in crude oil processing plant in east java area due to process fugitive emission. Sample is taken from 20 workers include work duration and weight of the worker also crude oil plant air quality monitoring is measured using direct-measure benzene detectors. In the benzene measurement on the crude oil plant in east java area, 2 spot sample is taken with resulting data 0.96 mg/m3 or 0.30 ppm and 0.86 mg/m3 or 0.27 ppm, and according to final manual calculation for safe benzene concentration with the result 1.12 mg/m3 or 0.35 ppm, all of those number are still below safe concentration limit by refer to minister of man power No.13 / MEN / X / 2011 regulation and The Occupational Exposure Limits (OELs) which have been adopted globally as a company standard which is 0.5 ppm as an eight hour time-weighted average (TWA8) and 1.0 ppm as a Short Term Exposure Limit (STEL) (averaged over fifteen minutes). But according to Minimum Risk Level (MRL) ATSDR 2007, those value already above threshold which is 0,009 ppm daily exposure for acute effect and 0,003 ppm daily exposure for chronic effect, Recommendation to control and reduce fugitive emission which resulting in number of benzene is by reviewing engineering design for equipment causing fugitive emission, and since this company regulation for respirator usage in benzene case are 0.5-5.0 ppm must use Half-face mask with organic vapor cartridge, 5.0-25.0 ppm use Full-face mask with organic vapor cartridge, and Greater than 25 ppm use Self-Contained Breathing Air (SCBA) then need to re asses all area which has an obligation to wear personal protective equipment (Half-full / full mask with organic vapor cartridge or Self contain breathing apparatus) by not only based on benzene level but also considering the exposure duration. .


Introduction
Oil and gas processing facility is place to separate raw oil from water, sediment, and unwanted gas. exposure, lungs are the major site of benzene metabolism (Arnold et al., 2013) 3 . Worker in here continually exposed by benzene from process fugitive emission which come from process fugitive emission on the oil and gas processing facility 4 .
The results of the measurement of benzene at two points in the Oil and Gas processing plant Industry in East Java are 0.96 mg/m3 or 0.30 ppm and 0.86 mg/ m3 or 0.27 ppm. These results are still below safe concentration limit according to minister of man power No.13 / MEN / X / 2011 and The Occupational Exposure Limits (OELs) which have been adopted globally as a company standard which is 0.5 ppm as an eight hour time-weighted average (TWA8) and 1.0 ppm as a Short Term Exposure Limit (STEL) (averaged over fifteen minutes) 5 . but workers who are exposed to benzene will still have a carcinogenic effect. A similar study at the Pancoranmas Depok gas station by Abdul rohim (2012), even though benzene concentrations at the site had yields below the safe concentration limit, but workers at the exposed area had a risk of carcinogenic effects at the duration of the lifetime exposure 6 .
The authors will measure the limits of the safe concentration of benzene in different areas, namely in the Oil and Gas Industry processing plant in east java region.

Material and Method
This type of research is an observational, cross sectional and descriptive study. The population in this study are all production operators in oil and gas company workers in the East Java region. The sampling technique is the total population, so the sample is 20 workers.
The research variables is benzene concentration in the workplace, worker body weight, worker height, respiration rate of ayworkers, length of day working, body surface area, weight of white mice, body surface of white mice, highest dose of toxin without effect on experimental animals NOAEL), Km factor in animals (Animal Km), factor Km in workers (Human Km), safe dose limit for toxins for workers (SHD), and safe benzene concentration in the air (safe C).
Data analysis in this study was carried out by using quantitative data analysis manually to determine the safe concentration of benzene for oil and gas company workers in the East Java region.

A. Characteristics of Try Animals and the Surface Area of Try Animals (White Mice).
According to Saridewi and Tualeka, the implementation of a toxicity test using experimental animals which is white rats 6 . In general, the human response to toxicity is qualitatively similar to the response of animals, so this fact forms the basis of extrapolation from animal to human data.
In  Based on data on worker weight and height of workers, the body surface area and the rate of respiration of workers can be calculated using the following formula.  Table 2 shows that the average body surface area of workers is 1.80 m2 and the average respiration rate of workers is 0.66 m3 / hour.

Worker Body Surface Area
The measurement results of the concentration of benzene at two points in the Oil and Gas processing plant Industry in East Java are 1.44 mg / m3 or 0.45 ppm and 1.18 mg / m3.

Tabel 3.
Distribution of Benzene Concentration in oil and gas processing plant in east Java region.

Measuring Location
Benzene Concentration (ppm) Those benzene concentration is still below the threshold limit value of 0.5 ppm in accordance with the provisions of the Minister of Manpower Regulation No.13 / MEN / X / 2011 concerning Occupational Safety and Health at the Work Environment. However, the concentration of benzene is above the Minimum Risk Level (MRL), the level of benzene inhalation exposure determined by ATSDR which is for acute exposure (≤14 days) = 0.009 ppm, moderate exposure (15-364 days) = 0.006 ppm, and chronic exposure (≥365 days) 8 The results of the Animal Km calculation are shown in Based on data on worker weight and height of workers, the body surface area and the rate of respiration of workers can be calculated using the following formula.

0.37
Those benzene concentration is still below the threshold limit value of 0.5 ppm in accordance with the provisions of the Minister of Manpower Regulation No.13 / MEN / X / 2011 concerning Occupational Safety and Health at the Work Environment. However, the concentration of benzene is above the Minimum Risk Level (MRL), the level of benzene inhalation exposure determined by ATSDR which is for acute exposure (≤14 days) = 0.009 ppm, moderate exposure (15-364 days) = 0.006 ppm, and chronic exposure (≥365 days) 8

C. Animal Km dan Human Km
The first step to determine safe dosage of toxin for workers is by calculating Animal Km and Human Km.  The results of the Human Km calculation are shown in table 5. Based on Table 5, the average Human Km in the oil and gas company environment in East Java is 36.70. One of the objectives of toxicology research is to be able to evaluate the safety limit of a substances in order to determine the safe concentration limit of a chemical begins with a toxicity test to determine the highest dose without causing effects on research animal or No Observed Adverse Effect Level (NOAEL).

Animal Km
There was a research from Swaen et.al (2010) revealed that benzene NOAEL is 3,0 mg/m 3 (0.94 ppm) or equivalent with 0,022 mg/kg which come from below calculation. 9 .45 The first step to determine safe dosage of toxin for workers is by calculating Animal Km and Human Km. D. NOAEL One of the objectives of toxicology research is to be able to evaluate the safety limit of a substances in order to determine the safe concentration limit of a chemical begins with a toxicity test to determine the highest dose without causing effects on research animal or No Observed Adverse Effect Level (NOAEL).
There was a research from Swaen et.al (2010) revealed that benzene NOAEL is 3,0 mg/m 3 (0.94 ppm) or equivalent with 0,022 mg/kg which come from below calculation. 9 And to convert unit of mg/m 3 to be ppm can use below formula.

DISCUSSION
The risks of benzene are caused by the increasing accumulation of benzene exposure in the body through inhalation. It is also in line with the research 8 36 ,85770701  9  39,81087364  10  42,29278006  11  41,75399653  12  39,52548736  13  38,36271775  14  38,65668924  15  39,81087364  16  45,14128763  17  43,86944611  18  41,48198063  19  38,65668924  20  45,88747517  Average  40,84 D. NOAEL One of the objectives of toxicology research is to be able to evaluate the safety limit of a substances in order to determine the safe concentration limit of a chemical begins with a toxicity test to determine the highest dose without causing effects on research animal or No Observed Adverse Effect Level (NOAEL).
There was a research from Swaen et.al (2010) revealed that benzene NOAEL is 3,0 mg/m 3 (0.94 ppm) or equivalent with 0,022 mg/kg which come from below calculation. 9 In this study invol work on the detected condition, outside oper exposed area for doing potential higher benzen in abnormal state (equip preparation for maint other breaking containm OHSAS 18001 (2 guidelines for Occu Hazards through elimi administrative and pe approaches. The ap substitution at oil and g

Discussion
The risks of benzene are caused by the increasing accumulation of benzene exposure in the body through inhalation. It is also in line with the research of Maryiantari et al (2016), enter the duration exposure workers with a high level of exposure has adverse effects against the risk of developing health problems 11 .
In this study involving 20 outside operators who work on the detected benzene area. Under normal condition, outside operators will stay on the benzene exposed area for doing routine job, but there will be potential higher benzene exposure where the activity in abnormal state (equipment failure, equipment under preparation for maintenance, pigging pipeline, or other breaking containment job).

OHSAS 18001 (2007) provides specific control guidelines for Occupational Health and Safety
Hazards through elimination, substitution, technical, administrative and personal protective equipment approaches. The approach of elimination and substitution at oil and gas processing plant in east java will require big project means will demand high cost. For the technical approach can be done by making sure the preventive maintenance to minimize equipment failure, and continue re assessing area which producing harm benzene value and providing personal benzene detector to increase awareness when time to use benzene respirator protection as a personal protective equipment approach. 12

Conclusion
In the benzene measurement on the crude oil plant in east java area, 2 spot sample is taken with resulting data 0.96 mg/m3 or 0.30 ppm and 0.86 mg/m3 or 0.27 ppm, those number are still below safe concentration limit according to minister of man power number No.13 / MEN / X / 2011 and The Occupational Exposure Limits (OELs) which have been adopted globally as a company standard which is 0.5 ppm as an eight hour time-weighted average (TWA8) and 1.0 ppm as a Short Term Exposure Limit (STEL) (averaged over fifteen minutes), and also according to final manual calculation for safe benzene concentration with the result 1.12 mg/ m3 or 0.35 ppm, but according to Minimum Risk Level (MRL) ATSDR 2007, all of those value already above threshold which is 0,009 ppm daily exposure for acute effect and 0,003 ppm daily exposure for chronic effect, then control action needed to protect workers from benzene harm effect to worker occupational health, Recommendation is reviewing engineering design for equipment causing fugitive emission (review type of gasket on flanges, change to double seal on the pumps or compressors, and re-routing hazardous gas vent), and since this company regulation for respirator usage in benzene case are 0.5-5.0 ppm must use Half-face mask with organic vapor cartridge, 5.0-25.0 ppm use Full-face mask with organic vapor cartridge, and Greater than 25 ppm use Self-Contained Breathing Air (SCBA) then need to re asses all area which has an obligation to wear personal protective equipment (Half-full / full mask with organic vapor cartridge or Self contain breathing apparatus) by not only based on benzene level but also considering the exposure duration 4 .

Conflicts of Interest:
All authors have no conflicts of interest to declare.

Source of Funding:
The source of this research costs from self.
Ethical Clearance: The study was approved by the institutional Ethical Board of the Public Health, Airlangga University.