Man has relied on animal skins for clothing for centuries. Though leather is assumed to be environmentally friendly, new research shows that workers are exposed to many occupation dangers, high pollution and suffer from many ailments. In addition many dangerous and carcinogenic chemicals are released during the manufacturing process which exposes the communities to health risks and death.The manufacturing process
Leather is manufactured through tanning of skins and hides. Leather has lipids, proteins, salts and water. The most important element is collagen which forms the fibrous materials. The preparation process involves, preparation, tanning and crusting. The preparation process entails preserving, soaking, removing hair, fleshing, splitting, reliming, deliming, bating, degreasing and bleaching.
Tanning is perhaps the most imperative process and makes the material flexible and prevents the collagen protein from decomposing. Chromium tanning salts penetrates to collagen making leather resistant to microbial attack and cannot decompose.
Lastly the crusting process takes place. The process thins and lubricates the material. The main processes include, splitting, neutralization, re-tanning, dyeing, fat liquoring, drying and finishing.
Physical and chemical pollutants from manufacturing process
Workers are exposed to dust and fibers and grains from the raw material. These vary from 30-1200µm diameter while grains are less than 10 µm. Dust particles are less than 5 micrometers (µm). These particles are dangerous to workers at the tanneries as they cause many respiratory diseases such as bronchitis, asthma, inflammations, pneumoconiosis and other chronic lung ailments.
The tanning process is the main pollutant in this industry. According to Environmental protection agency(EPA) and center for disease control (CDC), workers and communities living near tanneries are exposed to vast quantities of salts, sulfides, acids fumes, and lime sludge. Dangerous chemicals such as coal-tar derivatives, oils, dyes, formaldehyde, arsenic, chromium salts are also released.
Arsenic and chromium fumes have been proven to be carcinogenic and have resulted to death of many workers and people living near tanneries in USA, UK, ital and Sweden. Common cancers caused by these materials include bladder, sinonasal, lymphatic and haematopoietic, oral/pharyngeal, lung, and stomach cancerUse of dust collection systems to control dust and fibers
To prevent exposure from dust and fibers, there is need for leather tanning industry to use dust collection and air pollution control systems. Various fume extraction systems and dust collection systems can be used to collect the air so as to remove dust, fiber and grains. Different dust collection mechanism such as bag filters, cyclone systems, manual dust collectors and air pollution control systems can be used. In Addition, centrifugal blowers can be used to pump in fresh air to reduce the concentration of tanning fumes on the employees. Both Batch and continuous leather tanning processes are highly variable and require customized dust collection systems to be designed and installed.
Tanneries also produce a number of chemicals such as sulphides, arsenic, formaldehyde and acids fumes. All these chemicals are very hazardous and should not be released to the air. Wet scrubbing systems and air control systems can be used to trap these gases and reduce the emissions to legally acceptable levels.