CHEMICAL HAZARD - How dangerous are organic solvents?

How dangerous are organic solvents?

How dangerous are organic solvents?

Solvents have various effects on human health, whether the exposure is by vapour, mist, or liquid form. They can enter the body by inhalation (breathing in), by swallowing, and through the skin. The way that solvents may enter the body depends on the volatility and fat-solubility of the solvent, and the resulting ill health effects are specific to each solvent. 
These can include:

• A narcotic effect, causing fatigue and dizziness. High doses may lead to unconsciousness and death. Exposure to large doses of solvents may slow reaction time and affect rational judgement. This may increase the risk of accidents both at work and outside, such as in the traffic on the way back home.
  
• Irritation of the eyes and the respiratory tract.
  
• Dermatitis and other skin disorders. Solvents clean and de-fat, not only the product in the process, but also the skin.
  
• Damage to the liver, kidneys, heart, blood vessels, bone marrow and the nervous system (e.g. Chronic Toxic Encephalopathy). Solvents can penetrate the skin and enter the blood circulation.
  

Direct effects after a single exposure generally require a high level of exposure, while prolonged or repeated low levels of exposure may lead to effects after a long period. Effects also depend on the health state of the individual (existing diseases, vulnerability).

The health risk of exposure to solvents depends on the specific solvent and on the level of exposure to the solvent. Solvents differ in their potency to harm health. For example

• Ethanol (CH3CH2OH), often consumed in beverages, is an example of an organic solvent that is only moderately toxic, and hence, can be drunk in relatively large portions (when diluted) without acute intoxication. In addition, swallowing is by far the only relevant exposure route as the air concentration must be uncommonly high to cause any observable effects in human.
• Methanol (CH3OH) has a rather similar chemical structure as ethanol, but the intake rate, potency to cause adverse health effects and the type of health effects differ significantly.

These differences have to be taken into account when setting occupational exposure limits (OELs). The OEL (8-hour exposure) for Ethanol can be over seven times that of Methanol.

Solvents also can pose a safety risk. Most of the solvents are volatile and flammable and they should always be handled with care. Some solvents produce vapours, which are heavier than air. These vapours may flow to floor, or in worst cases to spaces where ignition by a spark from welding or static electricity may light them. The vapours may also flash from smoking. Vapours of solvents can also accumulate in confined places and stay there for a long time, presenting risks for health and property.

For European Union policy see Council Directive1999/13/EC on the limitation of emissions of volatile organic compounds due to the use of organic solvents in certain activities and installations.

More information on solvents may be found at Legislation and at Practical Solutions on this site. Further information is available at the European Chemicals Agency (ECHA) and at the International Labour Organisation (ILO).

Source: https://osha.europa.eu/en/faq/frequently-asked-questions-on-dangerous-2/how-dangerous-are-organic-solvents