Occupational Health/Occupational Illnesses

Silicosis

Summary of the history

The laws and guidelines put up around occupational illnesses really put meaning into "regulations [being] written in blood." Some of the more notable events include the 1930s Hawks Nest Tunnel disaster, where workers, in addition to being put under working conditions akin to sweatshops, were also not given respirators. This is despite respirator guidelines being drawn up by the US Bureau of Mines prior to the disaster.

This is why seemingly draconian and strict OSHA regulations exist; somewhere along the line, one can bet that someone failed to absorb all the relevant safety literature, until disaster struck. Thus, voluntary guidelines are not enough: safety rules must be regulated.

History can repeat itself

Despite all the accumulated knowledge on silicosis, countertop cutters have, unbelievably, still gotten silicosis in the 21st century. This has resulted in a outright ban on engineered stone in Australia as of 2024-07-01, resulting in the loss of jobs.

To defend against safety laws falling into obscurity, and jobs being lost through outright bans, all workers, be it management or laborers, must also defend themselves by being aware of all the dangers in their work before committing to an unfamiliar job.

To sum up:

Report any concerns you may have to your Occupational Safety regulator; you might just save a life.
Even if your employer has followed all the requisite safety regulations, reporting will give you the context needed to be safe on the job.

The details

Regulatory context around the Hawks Nest Tunnel disaster

Pathogens

Summary of the history

In the 1990s, the weakened immune systems caused by the HIV-AIDS epidemic resulted in mass reactivations of TB in hospitals. A disease which had been all but forgotten about, due to antibiotics and sanitation, was suddenly making a comeback.

Federal Register documents from NIOSH, as well as the NIOSH TB guide (pictured) describe the noted failure of certain disposable Dust/Mist respirators, as well as surgical masks, when it came to preventing tuberculosis infections. This was a large impetus for the creation of 42 CFR 84 in 1995, which created commonly known respirator ratings such as N95 and P100, to represent the change in testing methodology only.

Don't get it confused: These ratings are not fit-tests, and never have been. The major change that 42 CFR 84 brought was the replacement of silica dust as a testing medium, in favor of NaCl (salt particles) or DOP (oily particles previously used for HEPA filter testing). Fit tests are regulated by OSHA under 29 CFR 1910.134.

Certain respirators do not require fit testing. These are called powered-air-purifying respirators (PAPRs) and are directly mentioned in the NIOSH TB guide. One should also note the required occupational use of PAPRs in places like Biosafety-Level-3 labs. For context, SARS-CoV-2, the virus that causes COVID-19, was rated BSL-3 until 2024, according to CIDRAP.

History can repeat itself

Enter the COVID-19 pandemic of 2020. Prior to COVID, during the 2009 H1N1 pandemic, randomized control trials showed little difference in outcomes for healthcare personnel wearing N95 respirators over surgical masks, usually not controlling for fit, or people getting infected outside a hospital. Likely due to the proliferation of RCT papers, after the H1N1 pandemic, the CDC recommended surgical masks over respirators, seemingly in contradiction to other CDC documents like the NIOSH TB guide.

Coincidentally, the US Strategic National Stockpile did not refill their supply of respirators, and, very quickly, shortages of N95 respirators began in the early months of 2020.

Thus, people were left, to find out for themselves, the flaws of non-approved non-fit-tested PPE—think surgical and cloth masks—despite the fact that their effectiveness was already known: absolutely terrible against TB, as described in the NIOSH TB guide. This became especially problematic during the Omicron outbreak.

Since Omicron, there have been many anecdotal reports on social media on people getting infected going to the hospital, likely caused by hospital personnel not wearing masks. Their complaints may have merit: In 2023, the New York Times noticed a decline in mask mandates among hospital workers. The scientific studies in that article note that the Omicron, a variant of SARS-CoV-2, at the time was already shown to cause increased mortality among cancer patients.

The details

What is less known is SARS-CoV-2 can exacerbate occupational hazards. One of the more troubling hazards is SARS' ability to infect brain cells. Another is its effects on the immune system, increasing the risk of infection from opportunistic pathogens. These symptoms, along with many others, constitute what is known as Long COVID.

Most of the time, pathogens alone did not constitute an occupational hazard outside of labs, crowded spaces like barracks, and healthcare settings like in hospitals. Most dangerous pathogens, prior to SARS-CoV-2, either didn't transmit very well, or were easy to treat. And SARS-CoV-2 might have been easy to treat, if it weren't for its propensity to change.

Rapid mutation rate of SARS-CoV-2

The R₀ of SARS-CoV-2 has increased considerably with variants. In fact, there is perhaps no better proof of evolution than the variants constantly being submitted to databases like GISAID. A SARS-CoV-2 Omicron variant caused encephalitis in 2022, in Children, in Taiwan. Omicron in general has seen its R₀ triple compared to the 2021 Delta variant, according to a paper by Ying Liu et. al. The virus has unpredictible risk.

Unpredictable risk is how the flu became deadly back in 1918. Just like how flu vaccines need to be adjusted every year to account for new mutations, the SARS-CoV-2 vaccine needs "boosters" every year. Unfortunately, re-vaccination rates are well below 50%, even in places with large economies, like the US. And despite an attempted push to vaccinate everyone around 2021, herd immunity has never been reached in developed countries, let alone the rest of the world.

Fortunately, there are controls that can be used that do not rely on human behavior. Looking at history can also help; especially since no vaccine was available for the 1918 influenza pandemic, given the state of medical science at the time. Thus, along with changes in behavior, anti-pandemic design had to built in buildings.

Pathogens outside the hospital

New mitigations

It pays to stay on top of the latest news on non-PPE mitigations. Even if an unsafe situation seems necessary now, that doesn't mean it will always be the case.

A paper titled Transient transmission of droplets and aerosols in a ventilation system with ceiling fans by Li Wenxin et. al. suggests that ceiling fans can be used, with other mitigations, to remove pathogens from the air.

More information

External links

Australia engineered stone ban - From The Guardian
[1] - Shifting flu vaccines
[2] - A paper by Ying Liu et. al.
GISAID - Global Initiative on Sharing All Influenza Data

Nextstrain - See also: latest variants

On Wikipedia