Occupational exposure limits, COSHH

Control of Substances Hazardous to Health Regulations (COSHH). Guidance on Setting In-House Occupational Exposure Limits (Regulation 7 (1990)... 

Risk Assessment, Occupational Exposure Limits and the UK COSHH Regulations... 

That was in effect what Imppened. In a letto to the Annals of Occupational Hygiene in 1989 seeking to clarify the position with regard to the new occupational exposure limits d tiie indicative criteria used to set them, following the implementation of the COSHH Regulations, the HSE Chairman of ACTS stated (Carter 1989) ... 

The COSHH Regulations introduce two new classes of occupational exposure limits maximum exposure limits (MELs) and occupational exposure standards (OESs). Both of these new limits apply to exposure via the inhalation route and will be used in determining whether exposure has been adequately controlled, if it is not feasible to prevent it altogether. For substances that have been given MELs, the level of exposure should be reduced so far as is reasonably practicable and in any event should not exceed the MEL. For substances with OESs it will be sufficient to ensure that the level of exposure is reduced to the OES. ... 

HSC (2002a). COSHH enforcement and the mle of OELs, Annex 4 Discussion Doctanent on Occupational Exposure Limits (OEL) fiwnework. Discussion Document, Chemical Ri Assessment Unit, HSE, London. 

A fundamental requirement of the CoSHH regulations is that the exposure of employees to hazardous substances should be prevented, or, where this is not reasonably practicable, adequately controlled. Exposure to harmful materials can occur by inhalation, by ingestion or by absorption through the skin but inhalation is usually the main route of entry into the body. The Health and Safety Commission sets Occupational Exposure Limits , or concentrations of substances in the air at or below which exposure control is considered to be adequate. The values for exposure limits are listed on the Oxford Physical and Theoretical Chemistry Laboratory home page (Oxford Physical and Theoretical Chemistry Laboratory, 2006). Other countries have their own regulations for minimizing risks to users of chemicals and it is recommended that these are consulted before carrying out the tests described here. 

A risk assessment to comply with the UK COSHH (control of substances hazardous to health) regulations is more easily undertaken when handling chemicals for example. It can often be readily estimated whether a given emission from an operation will exceed the accepted occupational exposure limit (OEL). If it is well below the figure, then no further action is necessary. 

The occupational exposure limits published in EH40/1989 changed their format as a result of the enactment of the Control of Substances Hazardous to Health Regulations 1988 (COSHH) and all earlier copies of EH40 should be discarded. Essentially these standards are in two parts maximum exposure limits (MELs) and occupational exposure standards (OESs). 

In the past, the HSE has incorporated the American TLV system in a Guidance Note which was published annually. This practice continued until 1984 when a UK system of limits was adopted. Since that time, there have been several types of UK occupational air quality standards including the two-tier Control and Recommended Limit and, until recently, the Maximum Exposure Limit and Occupational Exposure Limit. Both these two-tiered systems defined exposure standards with different requirements for legal compliance. These systems have now been abolished and replaced by the current single-tier Workplace Exposure Limit (WEL) system. The WeL system now forms part of the requirements for adequate control of exposure by inhalation under the COSHH Regulations 2002 (as amended) . 

The occupational exposure limits for the UK are published in EH40. Since April 2005, when the fifth edition of COSHH Regulations 2002 (as amended) was issued, the previous system of setting occupational exposure limits (OELs) as maximum exposure limits (MELs) and occupational exposure standards (OESs) has been discontinued. They have been replaced by a single type of OEL known as the workplace exposure limit (WEL) which has legal status under regulation 7(7)(b) of COSHH. Incorporated in the data on exposure limits contained in the HSE s publication EH40 are the Indicative Occupational Exposure Limit Values (lOELVs) adopted by the EU. 

Workplace exposure limits (WELs) were adopted in the UK in 2005 to replace maximum exposure limits (MELs) and occupational exposnre standards (OESs). Workplace exposure limits—longterm exposnre limits (eight-hour time-weighted average exposures) and short-term exposme limits (hfteen-minnte time-weighted average exposmes)—are set by the Health and Safety Executive (HSE) and pnblished in document EH40 (http //www.hse.gov.uk/coshh/tablel.pdf). 

Trace Components The trace components of landfill gas mainly comprise a range of alkanes and alkenes, and their oxidation products (aldehydes, ketones, alcohols and esters). Waste Management Paper 26 (DoE, 1986) lists 108 compounds, or groups of compounds found in landfill gas sampled at six different landfill sites. Many of these trace compounds in landfill gas are recognised toxicants when present in air at concentrations which exceed established toxicity threshold limit values (TLVs) or the Occupational Exposure Standards (OESs) set by the Health and Safety Executive. Anyone coming into contact with landfiU gas is therefore potentially at risk from the toxic nature of the minor components, and under the Control of Substances Hazardous to Health Regulations (COSHH, 1988), landfill operators are legally responsible for the health of employees and are required to comply with OES s and exposure limits set by the Health and Safety Executive (HSE). 

It is the inhalation of such material which needs to be assessed under COSHH. The maximum concentration of an airborne substance to which an employee may be exposed by inhalation under any circumstance is specified by regulation, as is the method of measurement. These maximum exposure limits are published in EH40 by the Health Safety Executive. A list of occupational exposure standards are also published according to which there is no evidence of injurious effect if not exceeded. 

Regulation 7(7)(b) requires that the WEL must not be exceeded. The conditions described in 7(7)(c) are as follows for a substance that carries a risk phrase R42, R42/43, R45, R46 or R49 for a substance listed in schedule 1 of COSHH for a substance which is listed in section C of HSE publication Asthmagens Critical assessments of the evidence for agents implicated in occupational asthma or any other substance which the risk assessment has shown to be a potential cause of occupational asthma, the exposure must be reduced below that limit to as low as is reasonably practicable. 

---