LOS ANGELES (CBSLA.com) — Port of Los Angeles and Long Beach truck drivers and warehouse workers went on strike this morning to protest the longstanding practice of classifying some employees as independent contractors.

The strike started at 6 a.m. and involved workers of several of the large companies that do transport business at the ports, including XPO Logistics, according to Barb Maynard, a representative for truckers and workers.

Truckers say they are being misclassified as independent workers so companies can keep their wages low and deny them health and unemployment benefits.

The strike is the 15th at the ports in the last four years, but port officials expect it will have “minimal” effect on operations.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)