Mercury is a heavy metal naturally present in the produced crude oil and condensate. PETRONAS Carigali Sdn Bhd (PETRONAS Carigali) operates in basins where levels exceed the norm resulting in accumulation of the heavy metal within the process line and an increased risk of exposure to workers during its operations.
Within Malaysia, the permissible exposure limit (PEL) and biological exposure indices (BEI) of Mercury are as per the American Congress of Governmental Industrial Hygienists (ACGIH) yearly published limits. However, these levels are of limited use for the oil and gas industry as well as for workers in Malaysia for the following reasons
Permissible exposure levels are based on continuous exposure of 8 hours a day for 5 days a week. This is applicable to mercury exposure in battery making factories and such. However, the usual exposure for offshore workers are two weeks offshore (exposure time) followed by two weeks onshore (non-exposure).
The BEI is based on the general American population. In some regions of Malaysia, locals consume seafood exceeding twice a day causing an ambient level of mercury on blood to be way above the BEI.
With this, the challenges faced by PETRONAS in dealing with Mercury exposure include government guidelines using ACGIH limits, lack of published data on mercury exposure studies in the oil and gas industry, no information on baseline levels of mercury in blood for local residents in different parts of Malaysia and limited local laboratory capabilities in analyzing for different species of mercury. On top of this, the most challenging issue is communicating mercury hazard information and explaining exposure data to workers.
In summary, this paper highlights the issues and challenges faced by PETRONAS Carigali in managing Mercury as a health hazard in the workplace and efforts to overcome them.