Substitution of toluene, benzene and cyclohexane in the treatment of leather for footwear manufacture

Number

335-EN

Section

General Section

Use

Sector

Manufacture of textiles, leather, fur

Function

Solvent
Tanning agent

Process

Industrial spraying
Other

Product category

leather treament products

Application

Treatment of leather for footwear manufacture

Abstract

In this experience two solvents were used for the tanning of leather for shoe manufacturing. Substitution was carried out because several workers were affected by a series of health problems which included vomiting, dizziness and headaches. The most alarming symptoms were epileptic seizures suffered by two workers after 10 hours of continuous work with solvents in a tanning process. The hazardous products were substituted by a solvent whose only harmful component is acetone. The company also decided to order pre-tanned leather to reduce the use of chemical products.

Substituted substances

1-Methoxypropan-2-ol

CAS No. 107-98-2 EC No. 203-539-1 Index No. 603-064-00-3

Chemical group

Glycol ethers

Classification: hazard statements

H226 Flammable liquid and vapour
H336 May cause drowsiness or dizziness

n-Hexane

CAS No. 110-54-3 EC No. 203-777-6 Index No. 601-037-00-0

Chemical group

Hydrocarbon, aliphatic, saturated

Classification: hazard statements

H225 Highly flammable liquid and vapour
H361f Suspected of damaging fertility
H304 May be fatal if swallowed and enters airways
H336 May cause drowsiness or dizziness
H373 May cause damage to organs through prolonged or repeated exposure
H315 Causes skin irritation
H411 Toxic to aquatic life with long lasting effects

Other adverse effects

The substance is: endocrine disruptor (SIN List), neurotoxic cat. 3 (Vela et al.) as listed in the Substance Database according to SUBSPORT Screening Criteria (SDSC).

Cyclohexane

CAS No. 110-82-7 EC No. 203-806-2 Index No. 601-017-00-1

Chemical group

Cyclic hydrocarbons

Classification: hazard statements

H225 Highly flammable liquid and vapour
H304 May be fatal if swallowed and enters airways
H336 May cause drowsiness or dizziness
H315 Causes skin irritation
H400 Very toxic to aquatic life
H410 Very toxic to aquatic life with long lasting effects

Benzene

CAS No. 71-43-2 EC No. 200-753-7 Index No. 601-020-00-8

Chemical group

Aromatic hydrocarbons

Classification: hazard statements

H225 Highly flammable liquid and vapour
H350 May cause cancer
H340 May cause genetic defects
H304 May be fatal if swallowed and enters airways
H372 Causes damage to organs through prolonged or repeated exposure
H315 Causes skin irritation
H319 Causes serious eye irritation

Other adverse effects

The substance is: 1 carcinogen (IARC), neurotoxic cat. 4 (Vela et al.) as listed in the Substance Database according to SUBSPORT Screening Criteria (SDSC).

Toluene

CAS No. 108-88-3 EC No. 203-625-9 Index No. 601-021-00-3

Chemical group

Aromatic hydrocarbons

Classification: hazard statements

H225 Highly flammable liquid and vapour
H361d Suspected of damaging the unborn child
H304 May be fatal if swallowed and enters airways
H336 May cause drowsiness or dizziness
H373 May cause damage to organs through prolonged or repeated exposure
H315 Causes skin irritation

Alternative Substances

Acetone

CAS No. 67-64-1 EC No. 200-662-2 Index No. 606-001-00-8

Chemical group

Ketones

Classification: hazard statements

H225 Highly flammable liquid and vapour
H336 May cause drowsiness or dizziness
H319 Causes serious eye irritation

Reliability of information

Evidence of implementation: there is evidence that the solution was implemented and in use at time of publication

Reason substitution

physical hazards
skin/respiratory sensitizing
other toxic effects
ED
ecotoxicity

Other type of alternative

Purchase of pre-tanned leather

Hazard Assessment

Substances to be substituted: The most hazardous substance contained in the substituted solvent was benzene, it may be fatal if swallowed and enters airways, may cause genetic defects, may cause cancer, causes damage to organs through prolonged or repeated exposure, is a highly flammable liquid and vapour, causes serious eye irritation and causes skin irritation. Toluene was another hazardous substance substituted. It may be fatal if swallowed and enters airways, is a highly flammable liquid and vapour, is suspected of damaging the unborn child, may cause damage to organs through prolonged or repeated exposure, causes skin irritation and may cause drowsiness or dizziness. Cyclohexane may be fatal if swallowed and enters airways, is very toxic to aquatic life, is very toxic to aquatic life with long lasting effects, is a highly flammable liquid and vapour, causes skin irritation and may cause drowsiness or dizziness. Another hazardous substance contained in the substituted product is n-hexane, it may be fatal if swallowed and enters airways, is toxic to aquatic life with long lasting effects, is a highly flammable liquid and vapour, is suspected of damaging fertility, may cause damage to organs through prolonged or repeated exposure, causes skin irritation and may cause drowsiness or dizziness. The substance is an endocrine disruptor (SIN List), as listed in the Substance Database according to SUBSPORTplus Screening Criteria (SDSC). . 1-Methoxypropan-2-ol is a flammable liquid and vapour and may cause drowsiness or dizziness. Alternative substance: The alternative product reduces significantly health and environmental risks although acetone is a highly flammable liquid and vapour, may cause drowsiness or dizziness and causes serious eye irritation Therefore the alternative product must also be handled observing the adequate preventive measures.

Description of Substitution

This substitution experience was carried out in a shoe manufacturing company located in the region of La Rioja, Spain. The case had very serious implications since substitution was not carried out until several workers were affected by health problems. In this case two toxic products were used. Both were solvent used in the tanning of leather to manufacture shoes. The problem surfaced when two female workers suffered epileptic seizures after 10 continuous hours of work using the solvent mix. Other workers had previously reported safety reps about symptoms like dizziness, vomiting and headache which caused a direct claim to company managers by health and safety reps. The facility was equipped with an air extractor that did not work adequately due to fact that the floor supervisors removed the protection screens. After the two workers had the seizures, the alarm caused the rest of the staff to stop working at the tanning station. The workers informed safety representatives who demanded an explanation from the company’s health insurance agency. The doctors from the agency considered that preventive measures were adequate and workers could continue with their tasks. Then the safety representatives turned to the union federation for support and considering the grave circumstances the representatives of the regional health and safety and environmental department (CC.OO. in La Rioja) took action. Company managers were cooperative with union health and safety representatives mostly because of the negative repercussion of the events (two workers intoxicated in a small community where the company was well known). Union representatives were granted access to company documents, files and workplaces. The purpose of union intervention was to detect the cause of the problem and solve it without appealing to labour inspectors. During the visit to the facility union experts found out that one of the workers affected by the seizures had worked continuously at the tanning station for two months. The basic task at this work station was the manual application (with a piece of cloth) of solvents to leather pieces to achieve a tanning effect. Natural ventilation in the working area was poor and the extractor did not adequately circulate the air since the floor supervisor had removed the protection screens because the slowed down the tanning process. Solvents were kept in big containers whose wide opening favoured evaporation. Workers did not have protection masks and their latex gloves deteriorated fast and did not guarantee an adequate protection. The work station had not undergone risk assessment and workers had not received information about the risks and preventive measures, neither had they gone through medical checks as part of a health surveillance programme. The products used by workers contained organic solvents of several chemical categories: hydrocarbons, alcohols and acetones all neurotoxic products that affect the central nervous system. Several are also carcinogens. After the visit, the union expert drafted a report and met with union health and safety representatives with a twofold purpose: improving working conditions at the work station and making company managers recognise a work accident or professional disease condition of the affected workers. One week after the intoxication, company managers ordered a private preventive service to conduct an environmental assessment of the organic vapours released by the company. The assessment report concluded that the exposure by inhalation was below the established limit values, although the measurements had been made taking as a reference value 6 hours of work per day, at the tanning station equipped with an adequate air extractor. The assessment report included the following recommendations:

  • Providing workers with active carbon masks, nitrile gloves and safety goggles as protection against possible splashes.
  • Reporting immediately supervisors or section managers about air extractors’ malfunctions
In the light of these events, given the alarm caused by the intoxication of workers and as a result of the pressure by union representatives, company managers introduced substantial modifications to the tanning station:
  • the working cabin was replaced by an unmodified one
  • workers shifted frequently to avoid exposure for more than 2 hours a day
  • mandatory use of nitrile gloves and self-filtering masks
  • relocation of the work station to an area with better natural ventilation
  • containers with dispensers for the application of solvents
  • substitution of toxic products
The union health and safety expert met with company managers and representatives of the private preventive service to offer them advisory on substitution. Company managers were favourable to substitution and to the improvement of working conditions in an attempt to compensate for the negative comments caused by the alarming situation. The trade union advisor suggested the substitution of the toxic solvent mix by acetone, a less hazardous substance. Substitution was quickly implemented and the toxic products were replaced by acetone. The alternative met the company’s quality requirements and no further changes to the working process were necessary. Company managers also decided to order pre-tanned leather to reduce the use of chemicals in the facility. Union health and safety representatives were actively involved in the substitution and their full intervention eventually achieved the improvement of working conditions. Nevertheless, all workers were informed of the process in a series of meetings organised by safety reps who reported that after this action, both managers and workers became more actively involved in preventive activities.

Case/substitution evaluation

This substitution case was of special interest given the highly dangerous solvents used which implied health and environmental risks. Combined and prolonged exposure to several toxic chemicals considerably increased risk levels. The implemented alternative is a substantially safer substance. However, it also implies certain risks and must be handled in observance of adequate preventive measures. This experience helped raise workers and community members awareness on the significance of toxic risk for human health and the environment.

State of implementation

Full capacity

Date and place of implementation

2008, Spain

Availability of Alternative

On the market

Type of information supplier

User

Contact

http://www.rioja.ccoo.es

Date, reviewed

November 26, 2021