Carcinogenic Properties of Trichloroethylene (TRI) Are Known Since a Long Time. in 1996

0017-01 ENETEK

Carcinogenic properties of Trichloroethylene (TRI) are known since a long time. In 1996 the Deutsche Forschungsgemeinschaft classified TRI as a proven carcinogen to humans. This classification has been confirmed and supported with additional data in 2010. In 2001, EU legislation (28. ATP to Directive 67/548/EEC) classified TRI as “Carc.Cat. 2” (now “Carc 1B” according to CLP).

In 2007 REACH Regulation came into force, and in 2010 TRI was included into the Candidate List with the clear expectance of incorporating TRI into REACH Annex XIV. In 2010, the German AGS (committee on hazardous substances) published the risk-based occupational exposure limit (3.3 mg/m³) associated with a low cancer risk level, deemed as acceptable (work lifetime risk of 4 EE-05).

Therefore, for all downstream users of TRI it was obvious since 17 years, that there is a need to substitute this carcinogenic substance. Since at least 7 years (since inclusion into Candidate List) it was clear, that there is an urgent need for substitution or – at least – for lowering occupational exposure below the risk based limit value of 3.3 mg/m³ (TWA).

In this context, it is neither understandable nor acceptable that in all these years no R&D program was conducted to test alternative solvents and/or technologies.

The obvious longstanding ignorance of the need to substitute the carcinogen cannot be accepted as a reason or a justification for a prolonged review period.

The risk characterisation in the AfA 0017-01 is based on WRONG preconditions. Trichlorethylene (TRI) is a carcinogenic substance without threshold mode of action (see also ECHA RAC/28/2014/07 rec 2). For this substance NO health-based exposure limit value, i.e. no Derived No-Effect Level (DNEL) can be derived, but a risk based exposure limit value may be derived. A risk based exposure limit always hat to be associated with an “acceptable” cancer risk, typically a work lifetime risk of 4 EE-05.

The reference to the “acceptable” cancer risk of 1 EE-06 per year (equal with 4 EE-05 per work lifetime) is also to be found in “Reducing Risks, Protecting People. HSE’s decision-making process” (published 2001 by HSE).

The same risk level (4:100,000 per work lifetime) is deemed “acceptable” in German regulation.

As shown in the AoA, there are some reasonable alternatives using NON-carcinogenic substances. Among others, n-hexane is a feasible alternative. n-Hexane is neither a proven carcinogen nor a suspected carcinogen.

For n-hexane a health-based OEL exists, i.e. a workplace air concentration below of which no adverse health effects occure. Due to current scientific knowledge this OEL is 180 mg n-hexane/m³ as 8-hour-TWA with a short time (15 min.) value 1440 mg/m³ (MAK Deutsche Forschungsgemeinschaft). Even though the DNEL is smaller (75 mg/m³), these limit value is more than 20 times higher than those for TRI. n-Hexane shows a vapour pressure not much higher than that of TRI.

Therefore the use of n-hexane provides a large margin of flexibility in operating the plant under different conditions, compared with an air concentration restricted to 3.3 mg/m³.

The use of DNEL values in the ES is contrary to the provisions of REACH (see Annex I.1.0.1). A DNEL of 54.7 mg/m³ for 8 hr shift (36.7 mg/m³ for 12 hr shift) is used in the AfA – instead of using a risk-based limit value.

An incorrect CSR (e.g. containing DNELs for a non-threshold substance) produced by the registrant of TRI cannot excuse the downstream user from applying appropriate data and proper RMMs. Furthermore, a downstream user has to communicate in upstream direction “any information that might call into question the appropriateness of the risk management measures identified in a safety data sheet supplied to him” pursuant to REACH Article 34.

Being in contradiction to the SEA document (chapter 2.6.2), there is no “safe level” (in the document designated as “DNEL”) for TRI.

Exposure Scenario 1: Use as process solvent in semi-closed systems (chapter 9.4):

Measurements (personal sampling) conducted outside the enclosures show high exceedances of the limit value. Shift exposure levels up to 49 mg TRI/m³ are reported (meaning a 15-fold exceedance of the exposure limit of 3.3 mg/m³). In endangered areas the mean air concentration is 23 mg TRI/m³ (invalid data or incorrect measured values had been excluded).

Even in the laboratory, there are up to 16 mg TRI/m³ in the air, pointing to a very poor occupational health standard in this facility.

All air concentrations were at least 4-times higher than the exposure limit (3.3 mg/m³). The exposure limit of 3.3 mg/m³ corresponds with an “acceptable” work lifetime risk of 4:100,000.

Even the mean exposure level (23 mg/m³) is 7 times above the exposure limit.

Since these measured values are 75th percentile values, 25% of air concentrations are higher than the cited levels and impose an accordingly higher risk on the workers.

Referring to a risk based OEL of 3.3 mg/m³, the exposure levels in “normal operation” are up to 15 times higher than this benchmark.

Static monitoring of workplace air outside the enclosure shows concentration up to 85 mg TRI/m³ (i.e. 25-fold exceed of the risk based limit), given as 90th percentile values.

Therefore, the workers underlying the Exposure Scenario 1 are subjected to a cancer risk up to 25 times higher than the “acceptable” cancer risk. This is not acceptable.

Implementation of more effective LEV and improvement of general ventilation could reduce the worker’s exposure to TRI in a considerable extent. These improvements are indispensable, in particular to comply with EU legislation on Safety and Health at Work [see Articles 5 and 6 of CAD (98/24/EC) and Articles 4 and 5 of CMD (2004/37/EC)]. It should be noted that EU Workers Safety Directives (as minimum requirements) demand for minimisation of workers exposure especially to carcinogens.

Suggested alternative:

If an authorisation should be granted for the use, it is indispensable to include an EFFECTIVE LOCAL EXHAUST VENTILATION of work zones combined with ENHANCED GENERAL VENTILATION into the conditions to be given in the authorisation according to REACH Article 60/8. This conditions should guarantee, together with ongoing air monitoring, a mean TRI concentration not higher than 3.3 mg TRI/m³.

Because the risk based exposure limit for TRI is heavily exceeded in the plant, any authorisation should NOT be granted without imposing conditions as described above, including air monitoring, on the applicant.