A.P. Green SK-7 Cement

Product Description

A.P. Green SK-7 Cement was a high-temperature refractory and pipe-covering cement manufactured by A.P. Green Industries, Inc., of Mexico, Missouri. Produced from 1953 through 1972, SK-7 was formulated as a trowelable, air-setting hydraulic cement intended for use in industrial environments where conventional materials could not withstand sustained elevated temperatures. The product was marketed primarily to steel mills, power generation facilities, refineries, and other heavy industrial plants where boilers, kilns, furnaces, and high-pressure piping systems required reliable thermal insulation and surface protection.

SK-7 occupied a specific niche in A.P. Green’s broader refractory product line. Unlike castable refractories designed for monolithic furnace linings, SK-7 was engineered to be applied by hand or trowel as a finishing coat, a patching compound, or a pipe-covering cement. Its workable consistency made it popular among insulators and refractory crews for sealing joints, smoothing irregular surfaces, and encasing insulated pipe runs in a hard, durable outer shell. The product was sold in bags and bulk quantities through industrial supply distributors and was widely stocked in maintenance shops at steel mills and manufacturing plants throughout the United States from the 1950s into the early 1970s.

A.P. Green Industries was one of the most recognized names in the American refractory industry. The company produced a substantial catalog of asbestos-containing cements, blocks, boards, and castables during the mid-twentieth century. SK-7 represented one product within that broader line, but it reached a wide range of tradespeople across multiple industries during its nearly two decades of production.

Asbestos Content

SK-7 Cement was formulated with chrysotile asbestos fibers suspended in a calcium silicate and hydraulic cement matrix. Chrysotile, also known as white asbestos, was the predominant commercial asbestos fiber type used in refractory cements during this period. Its flexibility, tensile strength, and resistance to heat made it a practical reinforcing agent in products that needed to bond firmly to hot surfaces and resist cracking under thermal cycling.

In a hydraulic cement matrix, chrysotile fibers served multiple functions. They reinforced the set cement against mechanical stress, reduced shrinkage cracking as the product dried and cured, and contributed to the product’s overall thermal resistance. The calcium silicate component provided structural integrity and served as the primary heat-resistant binder. Together, these materials produced a cement that could adhere to pipe jacketing, boiler surfaces, and furnace exteriors while maintaining its integrity through repeated heating and cooling cycles.

AHERA-era documentation and trust fund records identify SK-7 Cement as an asbestos-containing product manufactured by A.P. Green Industries during its production years. The asbestos content was an intentional design feature, not a contaminant, and the fiber loading was sufficient to present a significant inhalation hazard during mixing, application, and removal.

How Workers Were Exposed

Exposure to asbestos from SK-7 Cement occurred across several distinct trades and work tasks. The product’s physical form — a dry powder that required water mixing before application, and a hardened cement layer that required cutting or grinding for removal — created multiple points at which airborne chrysotile fibers could be released.

Insulators (AWIU) were among the most frequently exposed workers. Members of the Asbestos Workers International Union applied SK-7 as a finishing coat over pre-formed calcium silicate or magnesia block insulation on steam lines, process piping, and boiler systems. Mixing the dry cement powder in buckets or troughs released clouds of fiber-laden dust. Troweling the wet cement over pipe runs and smoothing irregular surfaces generated additional airborne fiber. When sections of insulated piping required repair or replacement, insulators used knives, chisels, or grinders to break away the hardened SK-7 coating, a task that released concentrated fiber into the breathing zone.

Refractory workers applied SK-7 to furnace walls, kiln linings, and high-temperature process equipment. Work in confined spaces such as furnace interiors or boiler fireboxes meant that airborne fibers had limited room to disperse, resulting in elevated personal exposures. Refractory crews also performed hot patching — applying fresh cement to still-warm surfaces — which could cause the wet material to steam and partially dry rapidly, potentially releasing additional fiber.

Pipefitters worked alongside insulators on pipe systems and frequently handled pre-mixed SK-7 or worked in close proximity to mixing and application tasks. In maintenance environments, pipefitters often cut into or disturbed pipe covering to access valves and fittings, unknowingly fracturing hardened SK-7 layers and releasing settled fibers.

Steel mill maintenance workers encountered SK-7 in some of the most demanding exposure conditions. Steel production facilities relied heavily on refractory products to maintain furnaces, ladles, and tundishes. Maintenance workers who repaired or replaced worn refractory linings often worked in dusty, poorly ventilated areas. SK-7 was used both in original construction and in ongoing repair cycles, meaning maintenance crews could encounter the material throughout a facility’s operating life.

Engineering controls and respiratory protection were inconsistent or absent during most of SK-7’s production period. Adequate hazard communication to workers about the risks of chrysotile exposure was not common practice during the 1950s and 1960s, and many workers mixed, applied, and removed SK-7 without protective equipment of any kind.

Documented Trust Fund / Legal Options

A.P. Green Industries, Inc. filed for bankruptcy protection in 2002 following substantial asbestos litigation liability arising from its refractory and insulation product lines. As part of the bankruptcy reorganization, the A.P. Green Industries Asbestos Settlement Trust was established to compensate individuals who developed asbestos-related diseases as a result of exposure to A.P. Green products, including SK-7 Cement.

The Trust is a Tier 1 compensation resource, meaning claimants with documented exposure to A.P. Green SK-7 Cement can file directly with the Trust under its established claim procedures and review guidelines.

Filing eligibility generally requires that a claimant demonstrate:

• A confirmed diagnosis of an asbestos-related disease (mesothelioma, lung cancer, asbestosis, or other qualifying conditions under Trust criteria)
• Documented occupational exposure to A.P. Green SK-7 Cement or other qualifying A.P. Green asbestos-containing products
• Exposure occurring within the Trust’s covered time period

Typical claim categories recognized by asbestos settlement trusts of this type include mesothelioma, primary lung cancer with confirmed asbestos exposure history, asbestosis, and other nonmalignant asbestos-related conditions. Claim values vary by disease category, supporting documentation, and Trust payment percentage in effect at the time of filing.

Workers who used or worked near SK-7 Cement during its production years — particularly insulators, refractory workers, pipefitters, and steel mill maintenance personnel — and who have since received a diagnosis of an asbestos-related condition should consult with a qualified asbestos litigation attorney to evaluate their eligibility for trust fund claims and any available tort remedies. Additional product manufacturers or premises defendants may also be identifiable based on a claimant’s full work history.