HC&S explains the Pa‘ia spraying incident

By A&B spokesperson Meredith Ching

This is my understanding of the situation you have inquired about. On October 23, HC&S conducted an aerial application of an herbicide, Clean Amine, on its Field 212, located along Hana Highway, just west of Paia town. We were attempting to eliminate a noxious weed, castor bean, from the field, as it shades out the crop and depresses sugar yields. Aerial herbicide application was required because the 16-month old cane is too dense to allow access for ground spraying, and the weed height exceeded the canopy of the cane.

The active ingredient in Clean Amine is 2,4-D, which is among the most widely used weed control chemicals in the world and is present in a number of substances labeled for residential use. For more information about 2,4-D, refer to http://www.24d.org. This product is labeled for aerial application, and applications were made in compliance with the pesticide label. The mix used on Field 212 was a very diluted formulation, consisting of about 2% of 2, 4-D by weight.

We fully appreciate that the helicopter’s presence was likely startling for the residents. By design, they fly very low when applying the agricultural substances, for the very reason of minimizing drift and applying the substances most directly on the plants. Further, with this type of application of Clean Amine, the substance is only released when directly over the targeted weeds (which are very visible above the cane).

Further, when HC&S undertakes aerial applications on its fields, we generally do so in the morning when wind speeds are lower and more predictable; gusts and variable winds typically occur later in the day. Wind characteristics are an important factor for aerial applications, and one that HC&S carefully considers prior to any application. A spotter goes along on all aerial applications, monitors and records wind speeds and directions, and watches for any visual signs of drift so that prompt action can be taken to address it.

On this day, the wind speed in the field was measured at 3-6 miles per hour prior to the start of the application, and the wind was blowing in the normal trade direction. Average wind speeds remained below 10 mph in the field for the duration of the application though there may have been occasional higher gusts. Under these conditions, any herbicide drift, if it occurred, would be carried away from the direction of the homes and businesses in Paia. The nearest homes to Field 212 are upwind, and separated from the field by the Paia Bypass road, a fallow buffer area, the Paia public parking lot, and/or Baldwin Avenue. Further, as shown in your photos, the plume of herbicide trailing the boom applicator was quite contained – there is no ‘swirl’, thus indicating that wind conditions were quite controlled and a fairly directed spray was achieved.

We estimate that the homes shown in image 4 of your photos are at least 250 feet from the nearest edge of Field 212, and at least 400 feet from the spraying activity, in the upwind direction. The other structures shown in your photos (e.g. images 7 and 8) are the restroom facilities at Baldwin Beach Park and the Paia Youth Center, both on the makai side of Hana Highway, also distant from the area of spraying and not in the direction of the prevailing winds.

Please be assured that HC&S takes significant precautions to control drift when it undertakes any crop protection chemical applications, whether by air or ground, and complies with all label requirements for the substances it uses. On this occasion, HC&S was using special nozzles to ensure coarse sprays that are less susceptible to drift and a drift control agent which reduces the formation of the fine droplets that are most susceptible to drift. Applications were being made as low as possible over the target weeds to minimize the influence of wind on the sprays, and the area of application was downwind of Paia homes and businesses. HC&S also observed a “no-spray” buffer zone of 300 feet along Hana Highway.

HC&S explains the Pa‘ia spraying incident | Maui News | The Moon over Haleakala

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