Should spray technicians have their blood tested?

Q. I own a growing company which primarily provides chemical weed control and fertilization services. As the company grows, I am placing a greater emphasis on safety. One question is in regard to blood work for spray technicians to assess their chemical exposure.

Are you familiar with this type of testing or know of any specific resources for additional information? Specifically, I am interested in learning more about the benefits/necessity of such testing, under what circumstances it becomes important and which tests are important and at what frequency. I am also seeking information regarding appropriate policies and procedures regarding results of employee tests and any legality involved.

A. A recently retired Pennsylvania pesticide regulatory staff member stopped by my office, and I shared your email with him. We had a long discussion about the pros and cons of blood testing for pesticide applicators. Let me share with you some of our thoughts and recommendations.

One, many of the chemicals that your personnel are applying for weed control on turf will not show up in blood tests, and even if they did, they may show false readings. Take for example 2,4-D or dicamba herbicides. Neither of these products is a cholinesterase inhibitor, so the blood tests that measure the status of cholinesterase would not change from one month to the next.

Cholinesterase is an enzyme in the blood that is important for the transmission of nerve system messages at the nerve synapse (there are millions of these in the human body). This is where nerve endings come together and a chemical (cholinesterase) is found between the nerve endings that helps the messages flow uninterrupted across the synapse. If a cholinesterase-inhibiting pesticide (malathion, sevin, or other carbamates or organophosphates) has been absorbed, ingested or inhaled into the body, and then moves through the bloodstream to the central nervous system, it can inhibit or tie-up cholinesterase.

When this happens, the cholinesterase is not available to help in the transmission of nerve messages. Physical symptoms of this inhibition of the critical enzyme include profuse sweating, headaches or dizziness, and the individual may feel like he or she is going to throw up. Heavy doses of cholinesterase inhibitors can also cause more severe symptoms that may be life threatening.

Two, essentially, there are no blood tests that accurately measure cholinesterase inhibition for technicians who are performing weed control on turfgrasses. In lieu of these blood tests, we suggest that your technicians take part in periodic and ongoing safety training that emphasizes the importance of personal protective equipment (PPE). I would spend some time and write up a comprehensive PPE program based on the PPE recommendations on product labels and MSDS.

Make the program as interactive as possible, meaning that you demonstrate, and then have the employees demonstrate their understanding and use of the PPE while applying pesticides. Make sure the PPE program is formally written and is an integral part of your safety training program. Please make sure that all employees who are trained on any aspects of your written safety program, sign-off (their signature) on their training, with the topic, instructor’s name and date of training clearly identified on the documentation.

Reminder: All new employees should be trained before they apply any chemicals, and follow-up training should be conducted on a regular basis, especially with employees who have been observed in violation of your company’s PPE policies and programs.

Also, make sure you have plenty of PPE in reserve so your technicians can obtain the chemical-resistant body suits, gloves, goggles, boots, and head and eye protection that will eliminate exposure to pesticides while they are making  applications.

Three, in high temperature places like Texas and during warmer weather, please don’t let your employees cut corners on wearing PPE.

I would agree that some of the PPE may be a little warm. However, not wearing PPE because of sweating is not an excuse. PPE only provides protection if it is fully implemented for each and every application. You can look for cooler examples of chemical-resistant body suits and skin protection if this becomes an issue with employees.

- Sam Steel, PLANET Safety Specialist