• Residues may be toxic or flammable/combustible (for example, fuel). These residues can cause illness, fire, or explosion.

• Liquid residues of hazardous materials must be removed from work spaces as thoroughly as possible before employees begin cleaning operations. [1915.13(b)(1)]

• Piping and pumping systems entering the work space must be disconnected, blanked off, and secured by a positive method, if they are possibly carrying hazardous materials. [1915.15(a)]
• Pumps within the system must be secured (for example, blanked or disabled). [1915.15(a)]

• Workers entering a space containing flammable, combustible, toxic, corrosive or irritant vapors, mists, or gases are at risk of fire and explosion, as well as health hazards.
• Cleaning operations may also generate concentrations of flammable, combustible, toxic, corrosive or irritant vapors, mists, or gases through interaction of cleaning agents, or reactions of cleaning agents with residues.

• Testing must be conducted by a Shipyard Competent Person (SCP) to determine the concentration of flammable, combustible, toxic, corrosive, or irritant vapors within the space.[1915.13(b)(2)]
• Continuous ventilation must be provided at volumes and flow rates sufficient to ensure that the concentrations of:
  • Flammable vapor is maintained below 10 percent of the lower explosive limit. [1915.13(b)(3)(i)]
  • Toxic, corrosive, or irritant vapors are maintained within the permissible exposure limits and below immediately dangerous to life or health (IDLH). [1915.13(b)(3)(ii)]
• When shipbuilding operations result in flammable/combustible atmospheres:
  • Air-moving equipment and its component parts, including duct work, capable of generating a static electric discharge of sufficient energy to create a source of ignition must be electrically bonded to the structure of a vessel or vessel section, or in the case of landside spaces, grounded to prevent an electric discharge in the space. [1915.13(b)(11)]
  • Fans must have non-sparking blades and portable air ducts shall be of non-sparking materials. [1915.13(b)(12)]

• The shipyard competent person report and/or certified marine chemist certificate must be posted in the immediate vicinity of the effected operation while work is in progress. [1915.7(d)(2) and 1915.14(a)(2)]
• Posted signs or labels must be presented in a manner (languages or symbols) that can be perceived and understood by every worker. [1915.16(a)] See Figure 5.
• A warning sign or label may be posted at the means of access if the entire work area has been tested. [1915.16(b)]
• If the space contains an oxygen-deficient or oxygen-enriched atmospheres, the space must be labeled "Not Safe for Workers" and workers must not enter until the oxygen content is between 19.5 percent and 22 percent. [1915.12(a)(2)] See Figure 6.
• If the concentration of flammable vapors or gases in the space is equal to or greater than 10 percent of the lower explosive limit (LEL) the space must be labeled "Not Safe for Workers" and workers must not enter until the concentration of flammable vapors is maintained below 10 percent of the LEL. [1915.12(b)(2)]
• If the space contains an air concentration of a material which exceeds a Part 1915 Subpart Z permissible exposure limit (PEL) or is IDLH, the space shall be labeled "Not Safe for Workers." [1915.12(c)(2)]
• Signs prohibiting sources of ignition within or near spaces containing or which have previously contained flammable or combustible liquids or gases must be posted at the entrance to those spaces, in adjacent spaces, and in the open area adjacent to those spaces. [1915.13(b)(10)]

• Workers entering spaces containing flammable or combustible vapors and gases are at risk of fire and explosion if the space also contains improper electrical equipment.
• Inadequate illumination in a space can lead to injuries from slips, trips, and falls.
• Workers entering inadequately illuminated spaces may become disoriented and fail to find the exit. This prevents the worker from safely exiting the space.
• Inadequate illumination can prevent workers from safely performing tasks.

• All means of access and walkways leading to work areas as well as working areas themselves must be adequately illuminated. [1915.92(a)] See Figure 9.
• Temporary lights must meet the requirements of 1915.92(b) and (c).
• Where temporary lighting from sources outside the vessel is the only means of illumination, portable emergency lighting equipment must be available to provide illumination for employees to move about safely. [1915.92(d)]
• Employees must not be permitted to enter dark spaces without a suitable portable light. [1915.92(e)]
• The use of matches and open-flame lights is prohibited.[1915.92(e)]
• In non-gas free spaces, portable lights must meet the requirements of 1915.13. [1915.92(e)]
• In spaces that have previously contained bulk quantities of flammable/combustible liquids or gas (such as after testing lube or fuel systems):
  • Only explosion-proof, self-contained portable lamps (for example, explosion-proof flashlight) or other electric equipment approved for hazardous locations by a National Recognized Testing Laboratory (NRTL), shall be used until the space is deemed "Safe for Workers." [1915.13(b)(9)] See Figure 8.

• A11.1: Illumination. ANSI Standard.

• The use of toxic, corrosive, irritant, or high pressure/temperature cleaning agents and their application equipment, may put the safety and health of workers at risk.

• A hazard assessment must be made to determine the appropriate PPE. [1915.152(b)]
• Also see the PPE requirements for specific cleaning operation hazards that may be encountered:

• Respiratory hazards
• Contact with corrosive or toxic materials
• Biological hazards
• High pressure hazards
• Excessive Noise