p-cresol

Exposure related observations in humans: other data

Administrative data

Endpoint:

exposure-related observations in humans: other data

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1997-2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Report well documented but not performed under GLP. Risk management measures (RMM`s) and operational conditions (OC`s) for the worker`s activities and the processes are documented and described in this report. Thus, process categories (PROC`s) could be attributed to the activities. According to the criteria described by ECHA guidance document R14 (2010), this reports meets the “High quality data band”. Data confidence is high, and the data enable a decision whether there is safe use. The number of data (63) is sufficient according to ECHA (2010). Variation and uncertainty of the data is low for both, the true variation in exposure and on the other hand by the knowledge about representativeness of the data. The full study report is attached in section 13: Air monitoring results, Allmendinger full study report.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Type of study / information:

In the two production-plants, both situated in Germany, workers have regularly been exposed to cresols. The relevant workplaces are examined repeatedly according to German technical rules of hazardous substances (TRGS 402). In total, 63 data from 1997 to 2011 are presented.

Endpoint addressed:

acute toxicity: inhalation

repeated dose toxicity: inhalation

Test guideline

Qualifier:

according to guideline

Guideline:

other: NIOSH No. 2001

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

all isomers: o-cresol, m-cresol, p-cresol

IUPAC Name:

all isomers: o-cresol, m-cresol, p-cresol

Method

Ethical approval:

not applicable

Details on study design:

Air monitoring data were generated in both sites at different work places. Typically, those places were selected where exposure of workers to cresols was expected, e.g. sampling and filling operations. Air sampling devices were fixed at the worker´s clothing nearby nose and mouth. The air was sampled in a thermal desorption tube (silica gel) by with a flow volume of approx. 200 mL/min (96 L/8h-shift), desorbed and analysed by gas chromatography according to an international accepted method (NIOSH method No. 2001).

Exposure assessment:

measured

Details on exposure:

Plant 1

General:
Part of the plant is located outdoor. Relevant indoor parts are ventilated by a general exhaust ventilation.

PROC 1,2,3,15 (handling of chemicals in continuous or batch processes, incl. sampling and laboratory use):
• Production vessels are closed during the process. Control of processes is performed from personnel either in a separated control room or on-site.
• Sampling is performed via a closed sampling system with small dead space. The sample is filled into the container via a septum needle. A second needle allows the displaced air to be released and to be directed to a local exhaust ventilation system. Sampling time is typically <5 minutes. The worker wears chemical resistant gloves and a face shield.
• A laboratory is available for analysis of products. The lab is equipped with laboratory hoods. It fulfils the requirements of the German technical rules of hazardous substances (TRGS 526).


PROC 8b,9 (filling operations):
• The drum filling station is located in a separate factory room with natural ventilation (cross-ventilation and intermittent ventilation). The station is equipped with a spot extraction device, and for drums-filling a semiautomatic filling station with immersed filling is used. The bung hole is enclosed by a box which is operated under reduced pressure. The liquid products have a temperature in the range of 20 to 69°C. For opening and closing of drums, the worker is situated in the near-field of the emission source. Workers wear chemical resistant gloves and protective glasses.
• The filling station for rail tank wagons and road tankers is located outdoors. For opening and closing operations (<15 minutes), workers have to wear a full mask with filter ABEK, chemical resistant gloves and a chemical resistant protective suit and a face shield. The filling process itself is performed semi-automatically using reduced pressure in the container. The worker controls the filling by means of an operation panel which is located in a 5 m distance to the emission source.


Plant 2

General:
Part of the plant is located outdoor. Relevant indoor parts are ventilated by a general exhaust ventilation.

PROC 1,2,3,15 (handling of chemicals in continuous or batch processes, incl. sampling and laboratory use):
• Production vessels are closed during the process. Control of processes is performed from personnel either in a separated control room or on-site.
• Sampling from reaction vessels is performed in a closed system via an immersion pipe. The temperature of the sample is about 200°C. The worker wears chemical resistant gloves and goggles.
• A laboratory is available for analysis of products. The lab is equipped with laboratory hoods. It fulfils the requirements of the German technical rules of hazardous substances (TRGS 526).




PROC 8b,9 (filling operations):
• The drum filling station is located in a separate factory room with natural ventilation (cross-ventilation and intermittent ventilation). The station is equipped with a spot extraction device. Immersed filling is used, operated under reduced pressure. The liquid products have a temperature in the range of 20 to 60°C. For opening and closing of drums, the worker is situated in the near-field of the emission source. Workers wear chemical resistant gloves and goggles. In case of filter change, workers wear a respiratory mask with ABEK filter.
• All other supply with cresols in this plant is performed via closed pipeline systems.

Results and discussion

Results:

-----short-term exposure
highest value: 1.87 mg/m³ (90th percentile: 0.9 mg/m³)
-----long term exposure
highest value: 0.91 mg/m³ (90th percentile:0.07-0.23 mg/m³)

----Discussion (Evaluation of Results)
ECHA (2010) presents rating criteria for workplace exposure assessment based on monitoring data. The criteria are reflected with the data within this report:
• Personal exposure data including that obtained by biological monitoring are available.
• The data presented are representative for the scenario “manufacture of substance”
• The data have been collected and analysed according to recognised protocols
• Raw data are available supported by information on key exposure determinants.
According to the criteria described, this reports meets the “High quality data band”. Data confidence is high, and the data enable a decision whether there is safe use.
The number of data (63) is sufficient according to ECHA (2010). Variation and uncertainty of the data is low for both, the true variation in exposure and on the other hand by the knowledge about representativeness of the data. Thus, even separate evaluations of routine operations and filling operations for the long-term exposure data are appropriate.

Any other information on results incl. tables

Short-term exposure

In the time period 1997-2011, 27 monitoring data have been generated for acute exposure (<15 minutes). An overview over the data is given in appendix 1. Activities could be attributed to PROCs 1,2,3,8b and 9. However it was not possible to evaluate the data on the basis of individual PROCs as the number of data is not high enough. Therefore, a statistical evaluation has been performed based on the total number of data. It should be recognised that most of the data have are below the limit of determination. For these cases, DIN EN 689 recommends to use the half of the limit of determination. This was done for the calculation of the 90th percentile:

Table1: Evaluation of short-term exposure data

	PROC1,2,3,8b,9
Highest value (mg/m³)	1.87
90th percentile (mg/m³)	0.9

                     

  

Long-term exposure

In the time period 1997-2011, 36 monitoring data have been generated for shift exposure (8h-time-weighted average, TWA). An overview over the data is given in appendix 2. Activities could be attributed to PROCs 1,2,3,8b,9 and 15. However it was not possible to evaluate the data on the basis of individual PROCs as the number of data is not high enough. It was however obvious that for the routine procedures PROC1,2,3 and 15, exposure data were rather low. Higher exposure was found for filling operations (PROC8b and 9). Therefore, one statistical evaluation has been performed, based on 19 data for PROC1,2,3,15. A second evaluation was performed for PROC8b and 9 based on 17 measured data. It should be recognised that most of the data have are below the limit of determination. For these cases, DIN EN 689 recommends to use the half of the limit of determination. This was done for the calculation of the 90th percentile. It should be recognised that a few data with relatively high limit of quantitation were eliminated as outliers prior to statistical evaluation:

Table2: Evaluation of long-term exposure data

	PROC1,2,3,15	PROC8b,9
Highest value (mg/m³)	0.3	0.91
90th percentile (mg/m³)	0.07	0.23

Applicant's summary and conclusion

Executive summary:

This report comprises air monitoring results from 2 productions plants manufacturing o-,m- and p-cresol. Each site produces or processes several thousand tonnes cresols per year. Exposure levels have been measured in the period from 1997 to 2011 related to at all relevant activities of the workers where exposure to cresols was likely. In total, 63 air monitoring data are available, 27 for short-term exposure (<15 minutes) and 36 for shift exposure (8h-time-weighted average, TWA). The results show that concentrations were up to 0.91 mg/m³ (8h-TWA) and 1.87 mg/m³ (15 min short-term exposure) with 90th percenentiles of 0.9 mg/m³ (short-term) and 0.07 to 0.23 mg/m³ (shift exposure).

Risk management measures (RMM`s) and operational conditions (OC`s) for the worker`s activities and the processes are documented and described in this report. Thus, process categories (PROC`s) could be attributed to the activities.