Last year across Britain, 144 workers were killed at work, with the highest number of deaths occurring in construction and agriculture, every one of whom was someone’s loved one, who went to work one day and never came home again.

Every one of these workplace fatalities was an individual tragedy, but there is a much bigger killer which gets far less coverage. These are workplace deaths which are a direct result of being exposed to harmful substances at work.

Over 12,000 people die every year as a result of being exposed to dangerous substances in the workplace, by far the biggest killer is deaths related to asbestos. Twenty years after asbestos was finally banned in Britain, deaths from mesothelioma, the incurable fatal cancer of the lining of the lung caused by breathing in asbestos, continue to rise due to the long latency period between exposure and the cancer developing. The latest figures from the Health and Safety Executive reveal that over 2,500 workers a year die from mesothelioma.

Construction workers are the group who are most at risk of being exposed to asbestos as public buildings and our own homes remain riddled with the substance. Without records of whether asbestos is present, either non-existent or of dubious quality, workers are effectively dicing with death every time they drill into a wall.

It is not just construction workers who are at risk from asbestos. Unite has recently unearthed the scandal that defence workers who maintained Sea King helicopters for 50 years were exposed to asbestos as many of the aircraft’s components contained the material.

Shamefully the MoD has claimed it has no central record of the affected workers, many of whom are not aware of their potential exposure and it is refusing to take any effective measures to alert them to the dangers they are facing.

The MoD has now sunk to a new low, of refusing to provide further information to Unite, citing the ‘commercial interests’ of the contractors who undertook the work on behalf of the ministry, as the reason information can’t be provided.

Unite also fears for workers installing smart meters alongside householders present when work takes place.

Equally, it is profoundly disturbing just how many teachers and other workers in education succumb to asbestos-related illnesses. It is simply horrific that our schools and colleges are not free from this killer material.

Yet asbestos is not the only killer in the workplace. Over 1,000 people a year die from silicosis and many more are left fighting for breath due to having inhaled silicon dust over the course of their working lives.

These deaths are eminently preventable with simple measures to reduce dust in the workplace, also, the wearing of masks is highly effective in preventing exposure.

Meanwhile, Unite has lodged over 100 legal cases on behalf of members in the civil aviation sector who have been made ill by being exposed to toxic cabin air.

Other industries have specific issues. For example, this week Unite exposed how workers in the tyre and rubber industry are still being exposed to carcinogenic N-nitrosamines and how because of the Conservative government’s so-called war on “red tape” there is no effective regulating body to take forward Unite’s concerns and ensure a cut in emission levels.

Another growing area of concern are diesel emissions and, while these are often linked to living close to major roads, is also a major workplace issue. Workers in many different sectors report severe ill health caused by being frequently exposed to diesel fumes.

There are a number of key lessons to be learned and understood from all of these cases.

Firstly, all employers have a duty of care and should be taking adequate measures in order to ensure the safety of their workers.

Secondly, it is absolutely essential that workers always wear any personal protective equipment (PPE) that is issued to them and that employers ensure that it is well maintained and fits; women are often “offered” poorly fitting and therefore dangerous PPE. Poorly maintained PPE or equipment that does not properly fit is nearly as dangerous as not wearing any at all. Unite also argues that precarious workers and the bogus self-employed, have a right to be provided with PPE.

Thirdly, workers have an absolute right to not place themselves in danger. If you think you are being exposed to a dangerous substance, such as asbestos, you should have it checked out and you should not resume work until it is properly examined and you are given the all-clear by someone properly qualified.

Finally, and, most importantly, the reasons that workplace deaths have decreased are a result of the campaigning of unions. It was union campaigns which led to asbestos being banned and it which forced governments and employers to act to reduce deaths and injuries in the workplace.

On Workers’ Memorial Day, it is important to reflect on what unions have achieved but also to steel ourselves for the fights ahead to further reduce the needless and preventable workplace deaths that continue to occur.

Battles that are becoming increasingly difficult due to the government’s hostility to the vital lifesaving safety laws that are needed to ensure that unscrupulous employers do not play fast and loose with the safety of their workforces.

Union stewards and health and safety reps are our front line enforcers. We know from experience backed up by research that a unionised workplace is safer. That’s why laws that hinder unions’ ability to organise and represent workers must be torn up and replaced with tougher laws that protect our frontline reps from victimisation and blacklisting. It is a fight that will save lives.

Gail Cartmail is assistant general secretary of Unite the union.