In part one of this series, we discussed risk. To have risk, hazard AND exposure must both be present. Remember Risk = Hazard + Exposure. Then we discussed acute, sub-chronic and chronic exposure, and what those mean. Now it is time to dig beyond the types of exposure and look at the types of activities pesticide applicators perform and the weak points where exposure can occur. Now for Part II of Pesticide Exposure, What Activities Can Lead to Exposure?
Before pesticide ever leaves the spray system and is out as a treatment there are many steps and things that must occur, each of which can cause exposure. Furthermore, just because a treatment is complete doesn’t mean that the chance of exposure magically disappears. From grabbing the pesticide all the way to cleaning the clothes worn during application, each step has the potential for exposure. Some of the ways/activities that might lead to exposure are:
- Handling pesticide containers
- Mixing and loading
- Applying the pesticide
- Cleaning and maintaining spray equipment
- Cleaning up spills
- Work performed in areas that were previously treated
- Cross contamination
- Cleaning/Handling PPE and other clothing
Many pesticide labels will specify PPE for folks that are “handling” pesticides. Well, what does that really mean? Handling a pesticide simply means touching the container that pesticide is in at any point after it was opened for the first time. This means that the simple act of moving a pesticide jug from storage to a truck, would be handling if that jug had previously been opened. Even though the cap is on, and many assume the risk is low, it is still possible to be exposed to pesticides. Perhaps as you were pouring from that jug previously some splashed onto the handle of the jug, and it is now contaminated. If you grab that jug with unprotected hands, you could be exposed to pesticide. This means ALWAYS wearing the proper PPE when handling pesticide containers that have ever been opened.
Mixing and Loading
To properly apply most pesticides, they must be moved from their containers into application equipment. Mixing and loading is one of the highest risk activities for exposure, because it is the most concentrated form of the pesticide, and the applicator is the closest to the source. It is not uncommon for splashes and other mishaps while loading chemical. The hazard is high (more concentrated pesticide), and the exposure chance is high, making this one of the riskiest activities. Add to that the noise, moving parts, and demand on attention while loading and it is easy to imagine the chance for exposure.
This step in the process is the one that most people would associate with chance for exposure, because we are spreading pesticide into our treatment area. Additionally, at this point the applicator isn’t the only one at risk of exposure, now the environment and potentially other people could be exposed. This is where reading and knowing your labels and maintaining situational awareness are paramount. Unlike mixing and loading, it is less common for a final spray solution to be as concentrated, so the overall hazard may reduce, but the length of possibility for exposure is much greater. The application process can take time and that time is prolonged for potential exposure. Like mixing and loading, there are moving parts and great demand on the applicator’s attention, meaning accidents can occur. Read and follow all label instructions and maintain situational awareness during the entire application process.
Keeping spray equipment in good working order is a never-ending task, and of the utmost importance for having reliable machinery. Sometimes equipment will have problems during application. A spray tip might get clogged, a hose might leak, or pump might fail. If this happens during the middle of an application, then an immediate fix is required, meaning there is a chance for exposure. It can be easy to simply try and unclog a spray tip, or wrap a hose without thinking about exposure, but a spray mix is full of pesticide, and thus could lead to exposure. Although it may seem straightforward to wear PPE while performing maintenance in the field, how many think to do the same once the equipment is back in the shop? Even a properly rinsed and cleaned out spray system could contain pesticides. That clogged spray tip might have accumulated pesticide and not properly flushed in the field. Treat ALL application equipment as if it has pesticide in it to best protect against exposure.
This is an obvious source of possible exposure, pesticide spilled is pesticide that can come in contact. In fact, properly cleaning spills reduces the chance of exposure, but it must be cleaned properly and with appropriate PPE. Large spills are obvious, and applicators know to clean them, but we oftentimes fail to clean the small splashes or drips that can occur. The key with a spill is to clean it immediately, yes even the drip from a treatment hose should be cleaned once it is noticed. The longer a small spill like that is left the greater the chance it is forgotten and becomes a possible source of exposure. To best clean spills:
- Protect yourself first, PPE
- Stop the source of the spill
- Contain the spilled material
- Absorb the spill
- Collect absorbed spill
- Clean area with soap
- Properly dispose of contaminated materials
Working in Treated Areas
Working in areas that have had pesticide treatments is largely what the Worker Protection Standard (WPS) is all about. Activities such as harvesting crops that have been sprayed, walking through areas that have been sprayed, and otherwise being in a place that was recently treated, runs the risk of exposure. Pesticides don’t immediately disappear after they are sprayed, in fact in many cases the point is that they don’t. Proper communication of what was sprayed and where and keeping people and pets out of the treatment area as directed by the label are key for reducing this chance of exposure. If in doubt, ask if an area was treated with pesticides and what restrictions might be in place. Signage, central communication boards, and telling all employees what was sprayed, when it was sprayed, and when it is ok to re-enter, the sprayed areas are all key things an employer can do to reduce exposure.
Everything discussed thus far has been directly related to the application of pesticides, or in areas where pesticides were put out. Cross contamination is about the transfer of pesticides from those areas into other spaces where exposure isn’t expected to occur. If we think about vegetables being harvested in the field, exposure might be on the minds of those harvesting the crops, but those processing it back in the plant might not. This is where things like post-harvest intervals and proper sanitation can prevent these kinds of exposures. Additionally, the PPE and clothing that is worn during application does work to protect the applicator, but because those items might be exposed to pesticides, they need to be handled differently. When removing PPE always remember dirty to dirty, clean to clean. So, PPE that is contaminated, say dirty gloves, should only touch the parts of the other PPE that might also be contaminated. Clean hands should only touch clean parts of the PPE. Soap and water, always washing your hand and PPE, can greatly reduce this risk. Clothes that are worn during application should be removed before getting into vehicles or even going into your house at the end of the day. These clothes should be laundered separately from other clothes, and the washing machine should be rinsed empty before any additional laundry is done.
The application of pesticides involves many steps, and each one has its own unique chance of exposure. The greatest protection against exposure is to always read and follow the label, while always maintaining situational awareness. Everything from handling pesticide jugs, to washing the clothes that are worn during application are chances of exposure, and as such a chance for mitigation and risk reduction. If Risk = Hazard + Exposure, then reducing the chance of that exposure reduces risk. This blog explored Pesticide Exposure: What activities can lead to exposure? and hopefully gave insight in how to reduce that exposure. The next blog in this series will explore How that exposure can get inside, or Routes of Exposure.