Tag: Occupational Health

Occupational Health and the Law: UK vs. US; I ask a question


A UK case report on Occupational Health and Safety, published in August, came to my attention today. Two NHS Occupational Health investigators from UK, Charles Poole of the Northern General Hospital, Sheffield, and M Wong of the Dudley & Walsall NHS Trust Health Center, presented two clinical cases associated with a relatively new occupational industry in that nation: “The separation of garden waste from domestic waste, its collection and processing in industrial composting sites, so as to reduce biodegradable waste going to landfill“.

It is well known that any kind of disturbance created in a given environment, for any reason, can often potentially release harmful substances in air in form of aerosols, or minute particles capable of floating in air. We have seen that with the yeast-like fungal pathogen, Cryptococcus gattii, which was found, via environmental studies, to be present in high concentrations in the soil of Vancouver Island (British Columbia, Canada), and to spread during dry summer weather likely as airborne particles (a.k.a. “propagules”). Release and dispersal of spores of various molds during large-scale air-disturbing activities such as construction, renovation and/or demolition of buildings is a well-studied phenomenon in the fields of Infection Control and Epidemiology; for example, see Krasinski et al., 1985; Streifel et al., 1983. The waste separation, collection and processing appear to be no different. The investigators write:

The process of composting organic matter encourages the production of bacteria, fungi, spores and endotoxins, which may be released to air in bioaerosols. Levels of bacteria and fungi up to 106 colony forming units/m3 in ambient air have been reported in relation to composting…

The problem has not been studied well at all in the population of waste-composting workers, because – as the investigators indicate – reports of illness in these workers are relatively rare. As a result, no safe levels of exposure to such potentially hazardous aerosols have been defined in this context, nor have been the exact conditions conducive to exposure; we don’t know if, and/or how much of, the exposure depends on variables such as composition of the compost, weather conditions, steps and systemic controls engaged during the separation and collection process.

In the existing clinical literature, one of the major culprits implicated in these environment-related diseases is the ubiquitous, spore-producing mold, Aspergillus, in form of its various species, mostly commonly Aspergillus fumigatus which is the etiological agent behind various diseases involving the upper (nose and upper part of the air-tube) and lower (lower part of the air-tube and the lungs) respiratory tract. Untreated or incompletely treated, these diseases can be severe and chronic. One particularly important manifestation is the Allergic Broncho-Pulmonary Aspergillosis (ABPA, in short), which is a complex or multi-component, immunologic, inflammatory response similar to allergies or hypersensitivities – which if not detected and treated early (with antifungals and steroid immune-suppressants) can lead to serious lung damage. ABPA is generally observed in people with certain debilitating conditions, such as cystic fibrosis, or immunosuppression, but rarely in otherwise healthy individuals. In ABPA, apart from classical respiratory symptoms, reduction in lung functions, and lung abnormalities observed under X-ray, certain allergy-related responses are noted in blood (more precisely, serum) – such as:

  • Type I hypersensitivity to bits and pieces of Aspergillus (all recognized as antigens by the immune system), leading to the excessive generation of allergy-associated antibody, called Immunoglobulin E (IgE). By its action, IgE causes release of highly inflammatory mediators, such as histamine, leukotriene, and prostaglandin, from immune cells, which have both immediate and long term deleterious effects.
  • Type III hypersensitivity to Aspergillus antigens, in which small complexes of these antigens with antibody run amok through the body, depositing in blood vessels, kidneys and joints – eventually leading to immune-mediated destruction of tissues at those sites.
  • Eosinophilia, in which eosinophils, a type of white blood cells, markedly increase in number in blood and/or tissues, a common occurrence in allergy and asthma, and in parasitic (worm) infections. Activated eosinophils, a member of immune defence, are capable of causing tissue damage by various mechanisms.

The UK case report describes two late-thirties, early-forties patients, both garden waste collectors by profession, and both diagnosed with ABPA at occupational health clinics; both responded to treatment and were released with the advice not to work with waste and compost. Another member of their team, who though not ill had symptoms of asthma and tested positive for high serum IgE to Aspergillus antigens (indicating exposure) was given the same advice.

The investigators go on to make some recommendations at the end of the report. They write:

Until the results of large epidemiological studies of garden waste collectors and industrial compost workers are known, the few case reports of ABPA […] would indicate that workers with asthma who are sensitized to A. fumigatus or who have cystic fibrosis, bronchiectasis or are immunosuppressed should not work with garden waste or compost, unless their exposure to airborne fungi can be controlled. Whether asthmatics who are SPT positive or specific IgE positive to A. fumigatus will go on to develop ABPA is unknown, but they should be made aware of the theoretical risk.

Annual health surveillance by way of a respiratory questionnaire and skin prick testing is also recommended for these workers. Other cases of ABPA or EAA in garden waste and compost workers should be sought and reported, until such time that the results of a national study of UK compost workers are known.

The recommendations gave rise to some germane questions in my mind. These are, of course, valid from a clinical standpoint, and made keeping the health and welfare of the patients in mind. But given that these are related to occupational health, how do these situations play out from the perspective of the employer? How are these situations different in the UK as opposed to in the United States? For example:

  • Can/should the employers (say, a waste management firm) mandate pre-employment testing for Aspergillus-specific IgE and skin prick hypersensitivity testing?
  • Can/should the employers refuse employment to a person who tests positive for IgE and hypersensitivity because of a theoretical risk? Relatedly, can/should such an employee be made aware of this theoretical risk?
  • Should such an employee choose to ignore this theoretical risk and accept the job (or continue on the job after a diagnosis) and become inflicted with ABPA, can/should the employee be able to claim occupational exposure and Worker’s Compensation?
  • Specifically in the US context, can a Health Insurance company demand the results of these surveillance tests for a person engaged in the waste management profession, and if positive, treat this as a pre-existing condition and refuse payment in the event the employee becomes ill and needs treatment?

I don’t have the answers to any of these questions. Perhaps someone conversant with labor and/or occupational health-related laws would care to illuminate me in the comments?

Poole CJ, & Wong M (2013). Allergic bronchopulmonary aspergillosis in garden waste (compost) collectors–occupational implications. Occupational medicine (Oxford, England) PMID: 23975883

MSDS (and a bit of Monday morning nerd chuckles)

As every laboratory-based researcher knows, Material Safety Data Sheets (MSDS), nowadays often called simply Safety Data Sheets (SDS)*, are very important as sources of crucial information related to workplace safety and occupational health. These documents, associated individually with every laboratory chemical, contain information on the potential hazards (health, fire, reactivity and environmental) and instructions for safely storing, handling, and working with the said chemical. It also lists emergency procedures to undertake in case of accidental spillage of the material or unprotected exposure to the same.

As one can imagine, these documents, provided by the manufacturers of these materials, are an invaluable resource for formulating reasonable occupational safety and health programs at institutions for scientific research and healthcare in compliance with Federal and State regulatory requirements. The information in MSDSs is targeted towards anyone who works, or comes in contact, with the chemicals, which includes employers, workers, supervisors, healthcare professionals, and emergency responders, including firefighters. Therefore, in order to ensure that MSDS provides the required information quickly and easily, these documents are presented in an easily-readable format and written in a clear, precise and understandable manner, with instructions for looking up further information if necessary. In the US, the Occupational Safety and Health Administration (OSHA) of the Department of Labor determines the Hazard Communication (or “HazCom”) Standard (HCS), which specifies what kind of information must be included on these documents; Canada and European countries have their own similar agencies performing the same function.

So long, the MSDSs were required to have 9 categories of information. However, recently, OSHA has recommended that MSDSs henceforth follow a more comprehensive 16-category format that was established by the American National Standards Institute (ANSI) as a standard for MSDS preparation. According to OSHA:

By following this recommended format, the information of greatest concern to workers is featured at the beginning of the data sheet, including information on chemical composition and first aid measures. More technical information that addresses topics such as the physical and chemical properties of the material and toxicological data appears later in the document. While some of this information (such as ecological information) is not required by the HCS, the 16-section MSDS is becoming the international norm. The 16 sections are: (1) Identification (2) Hazard(s) identification (3) Composition/information on ingredients (4) First-aid measures (5) Fire-fighting measures (6) Accidental release measures (7) Handling and storage (8) Exposure controls/personal protection (9) Physical and chemical properties (10) Stability and reactivity (11) Toxicological information (12) Ecological information (13) Disposal considerations (14) Transport information (15) Regulatory information (16) Other information.

There are many ways to access the MSDS of chemicals. By law, the Health, Safety and Environment (HSE) offices of institutions are required to keep and provide copies of specific MSDSs. However, these documents are now available online also, from the websites of individual manufacturers, as well as from large online databases. Many universities around the world (including my own) have contracted with a chemicals management and MSDS repository system called ChemWatch to provide this information.


Being of a naturally curious bent of mind, I accessed ChemWatch via my institution’s HSE, and did a search for the MSDS for that important laboratory chemical present in various buffers and solutions, namely, Water. You know, water, aqua, agua, ap, paani, H2O, or more popularly, DHMO/dihydrogen monoxide; the same.

The MSDS for Water was largely unremarkable. However, there were some gems in there. A few instances:

Product Identifier
Product name: WATER
Chemical Symbol: H2O
Other means of identification: Not available. Erm… How about ‘visual’? No?
First Aid Measures
Eye/Skin Contact or Ingestion: Generally not applicable. Ahem! ‘Generally’?
Precautions for Safe Handling
Safe handling: Generally not applicable.
Other information: Store away from incompatible materials and foodstuff containers.
Storage incompatibility: None known. Ah! Well then.
Exposure Control/Personal protection
Eye and face protection: Generally not applicable.
Skin protection: See Hand protection below
Hand protection: Generally not applicable.
Body protection: See Other protection below
Other protection: Generally not applicable. I am not kidding. It really does say these.
Basic Physical and Chemical properties
Solubility in water (g/L): Mixes.
Flammability: Not available. Seriously? ‘Not available’?
Information on Toxicological effects
Chronic: Long-term exposure to the product is not thought to produce chronic effects adverse to health (as classified by EC Directives using animal models); nevertheless exposure by all routes should be minimised as a matter of course. Methinks this needs a precise definition of the manner of ‘exposure’.
Skin irritation/corrosion or Eye irritation: Not available. Does ‘shrinkage’ qualify?
Mutagenicity or Carcinogenicity: Not available. How about just ‘No’, or ‘None’?
Ecological information: persistence and degradability
Ingredient: Not available.
Persistence:Water/Soil Not available.
Persistence:Air Not available. Of course not. Stands to reason, right? How can WATER persist in ‘water/soil’ or in ‘air’?

Heh, a rare lazy Monday morning of nerdy fun… [- wide grin! -] I’ll get my coat. KTHXBAI.

* This new short form ‘SDS’… How’d it go with finding the Safety Data Sheet of that ubiquitous molecular biology lab reagent Sodium Dodecyl Sulfate? I am looking for SDS’s SDS. What, a grand-SDS?… I probably shouldn’t quit my day job for improv yet.