When working on a temporary platform over navigable waterways in Washington State, safety should be your top priority. Here's some general guidance based on the documents you provided:

1. Hazard Communication: Ensure you have access to Safety Data Sheets (SDS) for all materials being used 1, 2, 12. These sheets provide information on potential hazards, first aid measures, and necessary protective equipment [1].
2. Personal Protective Equipment (PPE): Always use appropriate PPE. This may include waterproof gloves, eye protection (such as dust- or splash-proof chemical safety goggles and a face shield), and suitable protective clothing [2].
3. Respiratory Protection: If the work area is poorly ventilated or if exposure limits may be exceeded, use a NIOSH-approved dust mask or filtering facepiece. Ensure respirators are selected and used under the direction of a trained health and safety professional, following OSHA's respirator standard (29 CFR 1910.134) and ANSI's standard for respiratory protection (Z88.2) [2].
4. Material Hazards: Be aware of the potential hazards associated with materials like cement, crystalline silica, and other chemicals. These can cause skin and eye irritation, respiratory issues, and other health problems 5, 12, 13.
5. First Aid: Know the appropriate first aid measures for potential exposures. For skin contact, wash with plenty of water and remove contaminated clothing [1]. For eye contact, rinse cautiously with water for several minutes and seek medical attention 12, 18. If inhaled, move to fresh air and seek medical advice if you feel unwell [3]. If swallowed, do not induce vomiting unless directed by medical personnel [3].
6. Environmental Precautions: Prevent materials from entering sewers and public waters 5, 12.
7. Hygiene Practices: Do not eat, smoke, or drink where material is handled, processed, or stored. Wash hands carefully before eating or smoking [2].

Remember that this is general advice, and you should always consult specific safety regulations and guidelines for working over water, as well as the SDS for each product you are using.