Comparison of Occupational Exposure to Carbon Disulphide in a Viscose Rayon Factory Before and After Technical Adjustment Petar Bulat et al. Institute of Occupational Health, Belgrade Yugoslavia Department of Public Health, University of Gant, Belgium Applied Occupational and Environmental Hygiene Volume 17(1):334-38, 2002

Study Objective Measure personal exposures to carbon disulfide in order to follow- up and verify the effect of technical modifications on worker exposures in selected departments and job titles of a viscose factory

Study approach Characterize exposure for different job titles by establishing TWA ambient concentrations and to compare those measurements with data obtained in a previous study. Differences in exposure between the two studies reflect the efficacy of the introduced technical improvements.

Carbon Disulfide - Chemistry CS 2 ; –highly volatile liquid –MW = –Sp. G. = –VP = degree C –Explosive 1-50% v/v in air

CS 2 Exposure Guidance OSHA –20 ppm; C 30 ppm ACGIH –TWA-TLV 10 ppm (31 mg/m 3 ) –Skin –BEI 5 mg/g creatinine NIOSH –1 ppm; 10 ppm/15 minutes

CS 2 Health effects - general –Neurological –Cardiovascular –Ophthalmological –Endocrinological –Nephrological –Gastrointestinal –Reproductive dysfunction

Sampling – where and who 3 departments –Viscose preparation Viscose preparator –Spinning Spinner First spinner Day shift Maintenance –Bleaching Bleaching department

Technical Adjustments Viscose Prep. Dept. General –Improve exhaust ventilation Personal –New type of fresh air RPE for viscose preparator for entering churns

Technical Adjustments Spinning Dept. General –Enclosures and exhaust ventilation spinning machines freshly spun cakes waste bins Personal – RPE Fresh air mask –Spinner and 1st spinner –Compulsory with spinning machines open Half face piece –Day shift spinner and maintenance worker –Compulsory when in spinning room

Technical Adjustments Bleaching Dept. General –Too numerous and substantial to document Personal –None given

Sampling and Analytical Personal sampling pumps –100 ml/min –Pre & post calibrated Samples with > 10% difference discarded –Total sample volume <= 25 L Gas/vapor sampling tubes –Charcoal tubes – 400 mg/200 mg –Serially connected to drier tube

Sampling and Analytical Tube handling post sampling –Ends capped –Mailed in refrigerated box Laboratory –Held frozen at –70 deg. C –Used NIOSH method 1600 Desorption of tubes GC mass spectrometry analysis

Data Integrity and Analysis A priori data culling –Per & post sample flow rate change of >10% –Backup section => 10% of front section Statistical parameters –Geometric mean –95 % CI SPSS/PC+

Two types of Personal Samples Collected Outside the respirator –Shoulder or collar Inside the respirator –Taped to cheek – fresh air RPE –Attached to a probe on the half face piece RPE –Sampled continuously RPE on or off

Sampling Data Job title#Inside/ # outside # monitored/ # employed Mean sample time Days of sampling Viscose Preparator15/56/684.8 ( ) 7 Spinner41/4432/ (94.5–106.6) 14 First spinner4/11 of ( ) 3 Day shift14/134/ ( ) 6 Maintenance5/209/990.4 ( ) 3 Bleaching Dept3/43/ ( ) 3

Results – Job titles Found changes in job activity vs. job titles between the two studies –Viscose preparator, spinner and first spinner were comparable –Day shift spinner, maintenance and bleaching department were different

Results – exposures(mg/m 3 ) Job TitlePresent Inside RPE Study Outside RPE Previous Study Viscose Preparator 10.1 ( ) 20.8 ( ) 90.2 ( ) 14.7( ) C i Spinner5.4 ( ) 8.11 ( ) ( ) First Spinner 6.3 ( ) n= ( )

Results – exposures(mg/m 3 ) Present Study CS 2 concentration (mg/m 3 ) Day-shift13.0 ( ) C i 32.4 ( ) C o Maintenance workers2.2 ( ) C i 3.9 ( ) C o Previous Study Spinning cake regulator147.2 ( ) Bathman2.0 ( ) Cleaner39.5 ( ) Still standing regulator51.5 ( ) Spinning head39.8 ( ) Plummer25.9 ( ) Dry worker small repairs41.4 ( ) Shift technician0.6 ( )

Discussion Spinner and viscose preparator jobs very regimented and fixed - partial shift sample OK 60% capacity this campaign vs. full capacity on previous study

Conclusions Significant decrease in worker exposure from –Enclosing and ventilating spinning machines and spun cake tables –Wearing RPE –Work organization

Conclusions Adjustments could be recommended in other viscose rayon factories to reduce CS 2 exposures after careful study of local production process

Problems Sample length on variable, non- repetitive job titles No documentation of RPE wear time Day shift spinners only sampled during work on spinner machines thus overestimating their daily exposure since that task was small part of total work activity.

Problems No reported measure of variability –Limits use of data by other researchers or other purposes No statement of confidence on GM even though stated as one of the calculations done Individual exposure data not reported No reported use of sample blanks Was best sampling strategy used

Lessons learned Always carefully describe work activity associated with a job title Always state a priori reasons for culling data samples Play close attention to sampling methods Do and report what you say