checkbox checking

I have a checkbox which is checking itself when it gets passed an object where the PK is 1,

Assume $posts is all the equipment in the table :

$posts= Equipment::model()->findAll();

<div class="checkboxes"><?php foreach ($posts as $equipment) {



                                    echo $form->checkBox($equipment, "[$equipment->equipment_id]equipment_id", array('autocomplete' => 'off'));

                                    echo $form->labelEx($equipment,"[$equipment->equipment_id]".$equipment->equipment_name ); 

                                    echo $form->error($equipment, 'equipment_name'); 


                            } ?>


In my table I have

equipment_id, equipment_name

1 Hard Hat

2 Hat/ Hair Enclosure

3 Safety Glasses

When i render a blank form, it checks "hard hat" by default. I tried autocomplete off, but if i delete "Hard Hat" from the database then it is fine. But if the ID is 1, then it seems to be checking my tick box.